I don't get why undoing a bad habit requires taking a day off. Get there early, work with the coach. Start undoing the habit in the game that day.

As for personal days, I guess I feel part of what you're agreeing to when you sign a major league contract is being ready and willing to play 162 games, as needed, barring injury or illness or whatever. Mental burn out isn't an option. I agree burn out can happen. I've experienced it myself at various times from various things. And I got through it. What you do is snatch recovery where you can - during sleep at night, during downtime and off days, and let's not forget, ball players do get off days. It's also possible to psych yourself up for things that will likely cause burnout. Like say, on an indie film shoot - where due to financial constraints they're putting in 16-hour days for a month straight. The director, et al, will be super burned out after that. But knowing this in advance, they can get prepare mentally. So, the MLB season is kinda grueling, agreed. But it's a pretty low-level type of grueling. You're playing a fun, low-impact game in beautiful parks before cheering fans, for a few hours a day, with lots of downtime, even during the game. Plus there's an end in sight. If it's early August, you've got two more months left. If any psychological "bucking up" needs to happen, it should be very doable.

A lot of this is moot anyway, because like you say, it's a good idea to keep backups fresh, and there can be many other reasons to sit starters. It's just the "rest for the sake of rest" that I don't like, especially when players are making multi-million dollar salaries specifically to play in those 162 games. A corporate CEO's job is more nebulous. If he goes golfing for a day, the company is not handicapped. At least not in the same direct way as if a team's cleanup hitter is absent from the lineup.