People who try to become vegetarians because they think they should rarely last. You need to want to. (context: vegetarian for 40 years, apart from the occasional bit of white fish).

Hmm. I think you sorta need to feel "you should" before you "want to", for most people. I have gone through periods of veganism, lacto-vegetarianism, ovo-lacto vegetarianism, ovo-lacto-pescatarian (and with and without poultry), etc. At the end of the day, my body was not built to be vegetarian in any capacity. It stops working properly without red meat, even (even when I try to supplement iron in other ways, my body literally does not function properly). I can go without chicken, but not other animal sources. It's a shame; I sort of didn't mind the food if it was prepared properly, but it is dangerous to suggest everyone can follow the same diet.