I was a vegetarian for about 10 years, and part of that time I was vegan. I went vegetarian after I went to an Earth Crisis show and got into a bunch of activist hardcore. I still support all the sentiment and activism and positivity, but I don't have the drive and passion for it that I used to.
It took me a really long time to go back to eating meat, and it was something that I agonized over for a very long time. It wasn't really an issue of athletic prowess or strength or whatever (in fact, the majority of the time that I powerlifted, I was vegan or vegetarian), but I came to a point where I didn't see the immorality in eating meat itself, just in factory farming. I also felt like a hypocrite if I ate vegetarian, but still supported factory farming through my consumption of dairy, honey, or even driving a car. Even through consumption of grains that were farmed in an unsustainable manner. It's a hard philosophy to see through to its logical conclusion, just like any other.
But it is said you save 80 lives a year by eating vegetarian. That always made me feel good.