I always wanted to become a vegetarian because I love animals very much and like Princ Rhaegar says: the way we "use" them is very wrong. So January 1, 2009 I stopped eating meat. After 2,5 month I was so weak and sick that I spend whole days on the couch.
I had a check-up and my vitamin B12 level was very low. Although B12 is in eggs, cheese and nuts too, meat contains much more of this vitamin. It turned out that I was unable to take the necessary amounts of B12 from a vegetarian diet.
So I started to eat meat again and my weariness disappeared almost immediately. (This disease is called Addison-Biermer disease.) There is a cure for it with lifelong injections, but B12 is called cobalamine in Latin (meaning cobalt), and I am allergic to cobalt, which means nobody dares to give me the injections.
So although I still want to be a vegetarian, I simply can't.