Things that are perfectly fine:
You: I don't like Doctor Who because I don't like Sci-fi. I like comedies and you should watch this one. I'll listen to your ramblings because you listen to mine. It's not his face or personality, I don't think he's a good actor.
Things that are not:
You: Doctor Who is so stupid. I will never ever watch it, I don't have to watch it to know it's stupid. Watch my show, it's sooo better. Oh God shut up, no one cares about your retarded ass shows. Let me interrupt you with my show rudely. Ewww he's ugly, this show is retarded.