I'm about to go off on a self indulgent ramble here so fair warning.
There are plenty anime that are forgettable. I'm sure you've seen many shows that technically did things right but in the end they didn't leave any sort of impression. There are series that just don't do anything for you. No investment in the characters or drama and no "x-factor" to add spice to it. Sometimes it's like you watch a show to watch it and you don't really care about it.
Slice Of Life is my most watched genre because of the warm and comfortable feelings it gives me. I have lived vicariously through the cast in series like K-On! and found relatable characters who would react the way I would and make the same mistakes as me in shows like White Album 2. I love that stuff, but that's another ramble. There is something else I love even more. It is shows with that x-factor.

Ever since I started watching anime when I was 12 I've been looking for that x-factor. I got into anime because of the insanity of Gurren Lagann. Such a crazy show but something you could take seriously and get really invested in. It didn't matter how stupid a robot with a giant drill was because it was awesome and it still is awesome. Anime is a medium that dares to be ridiculous and it can get away with the most insane ideas. That is why this is my favorite medium and nothing even comes close to it for me. There is such a well of insanity and quirkiness. That is why Gundam is a perfect example of the craziness that got me into anime and when I started watching the series last year it made me feel all those things anime made me feel when I got into it.
This is a franchise with a long history and lots of shows to watch. They will not appeal to everyone, although with the sheer volume of series there is bound to something for almost any viewer. Gundam appeals to me because it's insane, it's stupid, and most of all, it takes that insanity and stupidity seriously.
Gundam shows have a recipe that makes them so good. Insanely cool mecha, high melodrama, God tier OPs, weirdness, down right impractical concepts, cool girls, and burning spirit. A series like G Gundam has the dumbest stuff in the world but since it takes itself seriously I can both laugh at the silly Gundams and also be invested in it's world. Gundam Wing kind of sucks but I love it because of that. The show is just balls to the wall insane and it takes itself extremely seriously. The series treat their world and characters with respect which is what makes them so good.
I love SEED because it's a teen drama. The dramatics are what got me hooked and I loved the dynamic between the cast. I just like melodrama! I love when the pilots go through hardship and I love seeing them struggle and then gain confidence as the series goes on. This happened in all the good Gundam shows, the original, Zeta, SEED etc. I love the stories of the shows and their pacing. Whether it's the politics, military stuff or just the characters yelling at each other.
There is something so powerful in the scenes when the pilots are fighting in space and they yell at each other in a battle of ideologies. That is what makes Gundam so great, the greyness of it all. Not just good vs evil, it's people clashing over their ideals. Those scenes like the stunning finale of Char's Counterattack make it so good. Following Amuro and Char through the original series, watching them grow and change. It's always well earned when the pilots just get in their mobile suits and scream at each other.
G Gundam is full of yelling and it has a hot blooded energy and spirit that is so great. This show has a separate appeal to the other series and I can go on forever about how great it is. Gundam is full of these different types of series. I don't care for the shows after SEED as much. 00 is a good but not outstanding show to me, Unicorn is like a Marvel movie, you watch it once, enjoy the spectacle and then forget about it. But other people love 00 and Unicorn, and the other Gundam anime I have zero interest in personally like Iron Blooded Orphans and the whole Build Fighters thing. That's what cool about this franchise!
The God tier opening songs also help. If a Gundam show has a weak OP for me like After War Gundam X then it effects my enjoyment a little bit. We need those amazing songs to get us going and to keep the show alive after we're finished. The songs that we'll listen to over and over and feel power and excitement from. I have listened to the Gundam songs so many times, especially in the shower and in my car. They are just so cool and exciting.
The animation in the OPs can be downright stunning. Gundam Wing's second OP "RHYTHM EMOTION" is my favorite. It has one of the coolest things I've ever seen which is just the beeping at the beginning and then the Wing Zero blasting off. It's just so cool, and it could only of worked with traditional animation. Then we have the incredible sequences of animation for the other Gundams and an awesome shot of Wing Zero and Epyon that is better than the entire show itself. TWO-MIX's great song works perfect and adds a sense of drama.
https://www.youtube.com/watch?v=ICOwBtm8L_s G Gundam's opening "FLYING IN THE SKY" is an incredible burst of overwhelming and amazing testosterone. It's so badass and the way it connects song and animation is incredible. The pre-chorus has a feeling of powering up which we see reflect in the visuals as Domon sees his motivation for fighting and then gets ready to brawl. The song is so perfect, hyped up and powerful!
https://www.youtube.com/watch?v=q50VYTPkasc
Victory Gundam's OP "STAND UP TO THE VICTORY" is unskippable. The song is just pure power, an absolute jam that gives you all the energy you need for the day. The animation is insanely good. Pay attention to the details and the way the Victory Gundam moves. It's so fluid and there is so much thought put into the weight and impact of every motion. I don't care if I sound like a Boomer, traditional animation is the only way to go. There is so much life and soul put into these sequences, and you feel all the love and effort that the animators put in. Not to mention the amazing colours and shading that make it feel dynamic.
https://www.youtube.com/watch?v=OTYPjcrB9l8 Zeta Gundam has my favorite song of all the Gundam shows, the City Pop jam "Z~Toki wo Koete". The song is incredible and the animation is nice. There are some prime shots. The song is so cool and there are very few better ones I've heard in anime.
https://www.youtube.com/watch?v=lQrDASSYKmw 0083's "THE WINNER" has one amazing bit. The sequence of the GP01 rising from the ship, taking off and flying towards the GP02 is so cool that I can't handle it. The song is just amazing "I GOT A BURNING LOVE!". This sequence locks in with the song and the timing is so amazing. The added sound effects add a lot and it's just so amazing, it makes me feel alive and it brings joy and excitement to my stagnant grey heart of the last year. In a time like this where I haven't felt like I've been living life much at all Gundam has given me something to be excited about again. The opening of 0083 gets into my caveman brain and it gives me that powerful feeling of "THIS IS INSANELY COOL".
https://www.youtube.com/watch?v=CoplnxPv-J0 It might sound pathetic but you know, I don't care. These days feeling happiness and joy is something to be treasured. Being excited over something, no matter what it is, is great. I don't lose sight of all I'm thankful for in my life and I value my family and friends. I'm happy to be in college again, even if it's online, since it gives me a plan and path to the future. Anime, music and such is the stuff take enhances life and makes existence enjoyable in good, bad and everything inbetween times. I've seen so many anime that make me feel nothing at all. But Gundam has brought that feeling back and reminded me why I enjoy anime so much and the power of the medium. The inspiration it can bring to other parts of my life, such as my music. The power the songs can give me and the great feelings this form of entertainment offers.
Being actively involved and invested in the entertainment you consume is a great feeling. So often there is a numbing effect to the Internet and background noise type shows. So when you find something you truly enjoy, treasure that.
The Gundam shows are imperfect and that's why I love them. There is that x-factor, that ridiculousness, that balls out insanity. That is why I love anime. In shows like Mobile Suit Gundam, Zeta, Wing, Victory, 0083 and king of them all, G Gundam, that's what you get. There are so many unforgettable characters like Amuro, Char, Captain Bright, Emma, Domon, Master Asia, Cagali, Cima, Hamon etc. and insanely cool mobile suits. We all have those things we want to get out of any medium, for myself Gundam has every single thing that made me love anime to begin with. It has given so much to me over the last year and made my life more enjoyable in this era.
I just wanted to ramble about this. I might sound silly, but whatever. There is nothing wrong with being excited about something and sharing that. Go and find something you enjoy and feel excited about, it can have benefits on the rest of your life. There is never great entertainment to run out of. I believe there is a difference between passive entertainment and the stuff you find great. There are those shows and movies you just kind of have on to pass time and then there are those things you truly click with.
I could keep going on about the opening to 0083, the appearance of the Wing Zero in Endless Waltz, Char's speech at the UN type assembly in Zeta, the powerful emotional ending of the original series, the end of Char's Counterattack and everything to do with G Gundam. In short, I love Gundam. All it's flaws and silliness shape it's unique and enjoyable character. I've never been after perfect things, I mean KISS is my favorite band. I am after things that truly make me feel something.