Why do people hate vegetarians so much?

i understand it when vegetarians are pushy and try to force their beliefs on others, but in general why are they hated on? ive been one for a year now and im just curious why people get mad when they discover i am one. im not like, conceited or whatever about it.i dont go around saying im healtheir and better than you and how can you eat that stuff.. i dont even tell people most of the time. when they offer me food i say i already ate or im not hungry or something like that. my boyfriend told me when i can to his cookout to NOT tell anyone if a vegetarian... why is it such a big deal.. i dont eat animals so what?!