I am vegetarian since i was born, so it's like 16 years now.
I have only 2 problems - Being vegetarian it costs more to get all the vitamins you need and it's hard in our country, because of economical crisis. And all my friends are meat eaters so they tend to be sometimes jerks, but thank god some understand and they respect me, so i respect them.
Some vegetarians say that people needed meat to survive in old times, but nowadays you can get other foods to survive. Animals eat other animals, because they aren't as smart as us and can't make/get other kinda food as us, though i can be mistaken, because i think for some animals it's not healthy to not eat meat.