Phoebe Buffay

You surely know Phoebe in Friends, don't you?
She was always my favorite, but if you like her or not she is an excellent example of how vegetarians (and also vegans, but I'll come to that...) are portrayed in TV shows.
Phoebe is a vegetarian and Phoebe, oh wonder, is the weird one of the group.
She is the one that has all the weird ideas, that gets fed meat unknowingly and the one being friends with many other by the group considered as 'weird' people, of whom some are said to be vegetarians as well. She had a boyfriend, who was on a hunger strike, a friend who wouldn't shower until Tibet is free (which until today it isn't, so she must stink a lot by now) and such.
The idea of being vegetarian is in the series closely connected to being queer, what in Phoebes case manifests itself through her believe in spirits, the idea of aura and curses. Even so Phoebe is part of the group, a good friend, funny and honest, many people wouldn't want to friends with her in real life.
A while ago I came across a post on a website that was about the most noticeable illogical circumstances in Friends and one of them was the fact that the others were friends with Phoebe, as in real life she would be Monica's former weird roommate. But Phoebe is just an example for warm up.

Most other TV-shows portray vegans and vegetarians on a scale that starts with simple weirdness and ends with portraying them in a way that even I as a vegan start to dislike them. A quick example would be the 'dirty smelly hippie' Ted dated in How I Met Your Mother, who threw red paint in the face of the chef of the restaurant the group was eating in screaming 'Meat is murder!'. While meat in fact is murder, this kind of behavior makes people not like vegetarians and vegans and even so I understand it, when people act the way her character did, if you're out on a date with your non-vegetarian new boyfriend and his friends, I'm pretty sure most of us would do that...
Don't get me wrong here: I really like HIMYM! But in portraying vegetarians and vegans the show is kind of mean.
Unlike for example Southpark (were just everyone is ridiculed in the most offensive way possible) how vegans and vegetarians are portrayed in HIMYM made me like it a little less, even so it's still a great show. It simply feels a little like the writers really mean it and act in terms of carnistsic believes, when they rip on v/v's.

While we are on it: Southpark. I love it! The theme of how veganism and vegetarianism comes up in various episodes, but they really make it fun for me to watch, as they don't rip on v/v's so much, but more make fun of how society sees us. In the episode 'Fun with Veal' (6th season) Stan, Kyle and Butters are horrified, after they found out, that veal is in fact the meat of dead calves. They rescue dozens of baby cows and lock themselves and the calves in Stan's room and shortly after they are declared terrorists. Some of the food, that was send up to the boys contains chicken and beef and Stan, being ripped out of his carnistic illusion, refuses to eat any meat. While Cartman, who is with them (because the other boys made him help), tells Stan he'll become a 'pussy' if he doesn't eat meat, Stan in fact gets sick and weakly within a few hours, developing sores all over his face. It's really hilarious to watch! After the big showdown it all ends with Stan going to the hospital, where his doctor reveals that the sores on his face are actually little vaginas, because (as Cartman had said it) not eating meat had started to turn Stan into a giant pussy.
There is hardly any better critical view on what society thinks of v/v's, is there?

Maybe this one: Southpark - 15th season - 'Broadway Bro Down'.
Stan and his sister stay with the Feegans, a vegan family that always wears life jackets. There son is scared of everything and gets regularly beaten up, obviously because he doesn't eat meat. Throughout the episode he tries meat and considers it the best thing he ever tasted. Vegan food on the Feegan's dinner table is obviously very disgusting. While this is the subplot, I don't even need to go into it, you surely get what this says anyway: society thinks vegans are overly concerned about things, they are (coming back to Phoebe) weird and have queer ideas and most importantly any meal without meat (and dairy, eggs, etc.) tastes shit and makes you a pussy.

I'll leave you with that for now.