I do not have any problems with vegans, as long as, like Icedrags stated, they don't push their lifestyle onto others. Being a chef I get vegan orders every day, and it's fairly easy to adjust to.
Veganists on the other hand are the worst people in existence (besides arabs). I can't wrap my mind around why you wouldn't eat eggs, milk, cheese. Or even resist wearing wool clothes. And then I'm not even talking about the food they like to order. Like almost everything is made with either butter, milk, eggs, or any other animal related product. Just so annoying.
Aside from all of this, it is good to think about what you're eating. With a meat shortage in the world meat producents tend to treat their animals worse and worse, which affects the meat. The producents do not care about this, aslong they can sell in masses.
A couple of years ago I heard of a direction called "Dutch cuisine" where you eat 80% veggies, and 20% meat. Which, if everyone changed their diet, would cut 40%-60% of the meatuse.
Another thing you can change about your diet is eat more organic food (meat mainly). This would change the foodmarked more than by becoming vegan. By becoming vegan, the food producents won't feel too much. If you switch to organic they'll feel a change in food sales, which makes them focus more on producing organic food.