Different people will have different reasons why they become vegetarian or vegan. The difference between vegetarian and vegan is that dairy food may still include in the vegetarian diet, while in vegan diet, the dairy foods are not included. Both of them don't eat meat for sure.
In fact vegetarians' life is not dull at all. They have many choices. You can see that even Pizza Hut provides Vegetarian Pizza. So, in this modern world, vegetarian has become so common. You can find either foods in either eastern or western style.
Here's a video by Christine Marquette, a registered dietitian with the Austin Regional Clinic. She briefly explains to us how to become a vegetarian.