That sentiment always bothers me.
You're still writing off an entire medium based on limited exposure. I've seen lots of North American live action films that are crap, doesn't mean I hate live action movies.
And I say that as someone who dislikes MOST anime myself. On a technical note I can't stand many of the character designs, or the fact that most of it is on 3s or 4s, while western animation tends to be on 2s or 1s. Not to mention issues with the acting (And I don't mean the voice acting. That, I realize is the problem of the North American voice actors)
But I am not going to write off an entire medium based on that. Good animes exist, just like crap western animation exists, and if it seems like the overwhelming majority of it is rubbish, perhaps thats just because of the sheer volume of it produced.
(Equally annoying are the people who are batshit crazy over anything anime and seem to think its superior just because its anime. Don't get me started on that)