These are young men in their 20's for the most part. Kids. They make an enormous amount of money, but they have to perform every time out. Pitchers have to get hitters out. Hitters have to get on base. Success for one is failure for the other.
Most of us can (and probably do) coast through our jobs. We know how to do them and we mostly do them pretty well. Not outstanding, most days, but pretty well.
Doctors, nurses, cops and firefighters have to perform at their highest level every time. Military personnel in a war zone have to perform at their highest level every time.
Professional performers have to do it, too. Lives don't hang in the balance, but we've all been to a concert or a play when we knew the people on stage were calling it in. Do it too often and they find themselves playing 10 days at the Holiday Inn instead of one night at Yankee Stadium.
Quick anecdote which is covered fully in the Travelogues. A sand hill crane landed on the field yesterday and hung around for about three innings before it decided to move on. Reporters asked the pitcher about it, and then asked Manager Manny Acta.
Each said it was amusing but of no moment.
After Acta (who is from the Dominican Republic) had finished the post-game press conference he was walking away toward his he said over his shoulder: "That bird wouldn't have lasted three seconds in the Dominican Republic… It would have ended up in someone's pot."