Mentors may be wise, but it seems like there's one thing they don't have figured out: dating and relationships (okay, that's two things). Why is that? Why do these characters always seem to get the short end of the stick when it comes to love and romance? I know they have to help the hero, but what law says that they can't also maintain some kind of social or family life at the same time?
Here are a few examples off the top of my head:
[WARNING: Mild spoilers ahead]
Albus Dumbledore - I guess being the Headmaster of Hogwarts can be a pretty busy job. But surely he must have had some personal time, right? Or was that all spent on his complicated scheme to take down Voldemort? Come to think of it, it seems like most of the Hogwarts faculty flew solo (yes, Remus Lupin got married, but that was after he left the school). A curse, perhaps, like the one on the Defense of the Dark Arts position?