While none of the 7 1/2 habits of effective lifelong learners is very far out of my comfort zone, I guess that for me personally the hardest of these habits for lifelong learners is number 3: "View your problems as challenges."
Usually problems are just that - problems to conquer or get done with. Seems like the view here is that some folks view problems as obstacles, then stand around, worrying about the problems instead of doing something with them, to them, at them, whatever. But I don't often whine about problems or lollygag around while not doing anything about the problem.
So I suppose that I should sometimes just pause for a bit and see the different ways that a problem could be seen as challenging, instead of just tackling it by the first method that I come across.