I don't like asking my (windows network) users for their passwords, it doesn't seem like a good security practice. I also want to train my users to never give their password to anyone if they ask for it. But there are certain things that I just need to do while logged into a person's account. How does everyone handle this situation? Do they inconvenience the users by resetting their password and making them come up with a new one? Or is the practice of asking for users passwords the best way to do this?
Firstly as per @EricG most of the administration should be handled using a network administrator account, using group policies and the like.
If you need access to a users logged-in session the best way to approach this is to have the user login to their machine and then hand you the keyboard. That way you never learn there password, and the user can observe the steps you take. As noted in the comments this can also be done by various remote support, screen and session sharing applications.