To hit on what Five-Oh said about the trials of being a trainer, I know my trainer suffered greatly for the first while, and I've seen/continue to see trainers suffer greatly with their recruits.

While I am no seasoned veteran, I got a first personal whiff of that feeling of frustration the other day when working on a rather serious file and trying to co-ordinate a couple of people and their contributions to the file. There were some tense moments, as it was a file that took the whole day, a few hours of overtime, and then a few more hours the next morning to get all the information together.
I've been told by this time next year, I'll have already started with my next recruit..... I look forward to it.