I think it mostly matters on your age and your experience with anime/manga. You learn, you grow... I mean most of us wouldn't watch Scooby Do, but there was a time for most of us when we loved it.
Anime is the same. I don't criticize anyone for watching shonen anime even though I can't stand it.
I don't think anyone can recommend an anime to anyone else... there are 'good' anime, and there are 'popular' anime... many times those two are completely different, but it depends mostly on experience. I've watched one episode of Naruto in my life and though it was silly. Same with FMA. I've been watching 5-6 hours of anime every day for almost 20 years... I've seen thousands. Those two just do nothing for me. Does that mean people shouldn't watch them? Absolutely not. Some people love those anime to death, and good for them. It's great to have an anime you love.
If I recommend Genshiken or Haruhi, unless you've seen enough anime (meaning dozens of series) you won't like them, and you'll probably think they're 'bad'. There's nothing wrong with that, but remember an opinion is useless unless it's an *informed* opinion. So, you keep watching anime, you grow, you learn, you have more and more to compare your favorites to, you become informed. It's basically like trying to teach Einstein's Relativity to someone who hasn't had basic physics classes yet... relativity is just stupid unless you have a background to understand it.
I do see a lot of people recommending anime who themselves have only seen a couple of series... it's so tempting to jump in and comment... but, the more you grow, the less important it is to 'teach'... you just have to let people find the truth for themselves.
Whatever anime you're watching and enjoying, great. Just always try to remember some have years and years more experience, some have less experience... so, unless you are exactly where the other person is, you really can't know what anime they would like, or consider good.