I used to be totally in the bandwagon of "those annoying vegans trying to make people feel bad for eating meat". Now I agree - why shouldn't you shame someone for doing something bad? Buying and consuming animal products is bad for everyone involved: bad for the person eating them, the environment and the animals. We would shame corporations for polluting the environment and we would shame a person for abusing their pets in the way factory farming does animals, so why is it ok if they do it by proxy?
I read a nutrition book called "The China Study" about 6 months ago and it was the push I needed to seriously give veganism a try. I don't deny it, I love the taste of certain meats and at times I do miss them and I do occasionally still eat fish (sushi is my favourite food).
I'm feeling better in every sense. I was surprised to see that my body composition is actually better now, even though my protein intake is markedly lower (I was 95kg and ~14% body fat before and am 87kg and ~10% now, judging BF% with calipers so not exactly precise), my weightlifting strength is up, my cardio endurance is improved, my skin is _hugely_ clearer and I anecdotally seem to have more energy - I definitely feel less lethargic after eating. My biggest concern was loss of muscle mass given lower protein intake, somehow I am looking better and feeling stronger than before. I'm eating around 3-600g of carbs per day (!) which is all coming from whole fruit and veg, which seemed totally ridiculous to me before coming from a close-to-paleo high fat high protein diet.
FWIW I'm a 22 y/o male and consume around 3-4000 cals/day and work out 5-6 times per week so YMMV.