Originally Posted by Anon La Ply
That's interesting. I flatted with a strict vegetarian for years and he was grumpy.
However, I suspect the most likely correlation is that people become vegetarian because they are grumpy people - and one thing they get grumpy about is humanity's thoughtless cruelty to animals and damage to our environs.
I was grumpy long before I went veggie. If anything, I feel calmer and more affable since I stopped eating animal flesh for every meal of every day.