Well, I'm kind of amazed this thread has gone in the directions it has and come all the way back around, so as I don't think I ever gave my view I'll throw it in now.
A guy's gotta do the best that he can, and part of that is knowing when to quit. I could throw in a whole bunch of old saying here, like "A Man's Got To Pick His Battles Son" but the bottom line is that you're not going to be the best person ever and no matter what you do, you're never going to be able to do it perfectly. You need to balance your life. You have to do only what you're comfortable with on a moral, physical, and emotional level. If someone tries to guilt for doing as much as you can but not going to extremes above and beyond the call of duty, you have to just take it in stride.
So if you're the world's best surgeon and you want to take a break, fuck it, take the break. You've already saved countless lives, and you're sure to save countless more between vacations. Sure, people will die while you schmooze, as people are wont to do, but in the big picture people will always be dying. You choosing to take a vacation instead of work nonstop is not the best thing you could ever do according to hardass nun morals, but that does not at all discredit the good you do for the world when you're not sipping drinks in Tahiti.