The initial process of mentoring takes considerably more time and effort than doing it yourself, and it can feel like a waste of time if the "merely proficient" never reach the level of competence you have.
It may be the best thing to do under the circumstances, but it's hard, especially if you are a geek who has spend most of his live doing stuff rather than delegating the doing part.
"The initial process of mentoring takes considerably more time and effort than doing it yourself,"
Well, I suppose I can't honestly say "you're doing it wrong", but I can say "you're doing it differently than me". But then, even when I'm mentoring I tend to expect that I'm mentoring someone who fundamentally wants to know, and is willing to put time in to learning whatever it is on their own, and I'm just coming in every so often and saving time on pointing them to the next place to go. I am lucky enough to be in a position where I can essentially count on that, and thus "mentoring" != "hand holding".
It may be the best thing to do under the circumstances, but it's hard, especially if you are a geek who has spend most of his live doing stuff rather than delegating the doing part.