The ability to see things clearly is cool water on a hot day. The ability to separate out one's own insecurities from the reality of science is hard, but valuable. Dealing with one's mentor takes a lot of both. Dealing with one's mentees takes both.
Some days I find it is the past mistakes, when I couldn't see clearly, that bother me the most, not the current issues. Why didn't I just X or Y or even Q.
But I didn't, and time flies like an arrow (fruit flies like a banana), in one direction. As a teacher in my high school used to say in busy crowded hallways: Travel, kid, travel. Move on, move on.