I have heard that hitting a MLB fastball is the hardest thing to do in sports.
I don't think it's all that hard to hit a fast ball; it's all a matter of getting your reflexes right and your timing down. I've hit fastballs in the 85 to 88 mph range, and I'm not all that great. If the pitcher stays at about the same speed, I think just about any person of average athleticism can eventually make consistent contact, although it would obviously take some time to get used to.
What's difficult is hitting a fastball when you don't know if the next pitch is going to be a fastball, or a curve, or a splitter (which absolutely suck), or a slider, etc., etc.
True, but Baseball is the one sport where if you only have success 30% of the time (on offense), you go to the hall of fame.
I honestly think excelling throughout an entire NBA season is the hardest thing in sports. First off, you have to win the genetic lottery to even be eligible. Then you have to be able to run countless miles several times a week in between cross-country flights. And then theres the confidence, agility and finesse to score at will.
Most every other sport can be dominated through shortcuts (steroids) or repitition of practice. Not the NBA though. I can practice my post moves all I want, but at 5'11" - I have no chance at succeeding.
I've always felt pro basketball players are the best athletes in the world. The combo of size, agility, and endurance -- both physically and mentally -- is unparalleled.