I realize that I am, on average, at least 6 years younger than you are. I understand that you have more experience with small children and in the school system. However, I do wish to note that I have a degree from a rather challenging college. In other words, I'm not an idiot. I'm inexperienced. There is a difference.
Please, if I'm doing something that strikes you as odd, or something that you know flat-out is just not right, tell me politely. I realize I'm young, but I still merit respect. Don't tell me that I'm using the wrong copy machine, and when I express my ignorance of this fact, singsong (not quite under your breath) "Someone needs a training on this!"
Patronizing me won't help. It may make you feel better, but it does nothing for my relationship with you. It only breeds contempt and resentment.
(Goddamn holier-than-thou first grade teachers!!!!)