Theres loads of reasons, but the biggest one for me is:

I used to be a meat eater. My family had pet chickens for years. 2 of my chickens were rescued from battery farming. Their feathers were ugly (torn up and ragged) from their early lives - we could SEE the suffering they endured in their shakes, appearance and fear of humans. They eventually came to love us, and we them. When a fox got into their enclosure and massacred all 4, I was devastated, ruined. We buried them.

I never made the fragile connection (as many meat eaters don't) between life and death. That event made me question everything I did and believed. I questioned my own morals. It disgusts me to see a slab of meat, blood dripping and stinking. I just think of the life that has been ripped from existence. I've seen death and it's awful. No-one inherently wants to die and I don't want to kill.