Let's see now. According to Consumer Trends, 83% of Americans (Vegans only make up .5% of the population) have to drink coffee every single morning just so they can wake up for the day.
Then in the afternoon they have to drink even more coffee. Then companies started coming out with energy drinks just so these guys can get through their day without feeling so tired and lethargic all the time. They came out with drinks like Monster and 5 Hour Energy filled with tons of crap that's not good for your health and people actually drink it (there are actually a lot of deaths attributed to Monster and 5 Hour Energy and other energy drinks).
While your post about coffee-drinking Americans may be true, it's irrelevant to the discussion at hand. Most Americans lead sedentary lifestyles and gorge themselves on processed junk; of course they're going to feel like crap, whether they eat meat or not. A vegan who only eats processed foods and is lazy will probably have the same energy levels as the average unhealthy meat-eater. I've also read reports of people going vegan who developed medical issues over time due to severe nutritional imbalances. If you cut meat out of your diet completely, you really need to be on top of your game to ensure you get all your necessary nutrients. In fact, many doctors warn people from putting their children on vegan diets due to vegan-related deaths. I've heard there's even people who put their pet dogs and cats on vegan diets...
Oh yeah, that Einstein quote you mentioned isn't good advice; fatty acids are essential for us.
I don't think we're going to agree in the end, but to each their own. I don't eat meat often, and have gone months without eating it and felt fine. Would I cut it out completely? No. Would I recommend vegan diets for children? Of course not, that's inhumane.
http://naturalhygienesociety.org/diet-veganbaby.html