When you leave a position, you are often asked to do an exit interview. How should you handle it?
If you are taking a position in the same company, only tell them good things. Resist the temptation to explain how you could have been handled better, or items that have frustrated you. Tell them you learned a lot and you appreciate the time people gave you. Explain how what you learned in the position helped you get a promotion.
If you are leaving the company, feel free to tell them the truth about why you are leaving. If you have a good relationship with your supervisor, you can offer some feedback on how to improve. But there really is no upside for you to offer feedback as you leave.
Giving feedback is as art. You have to have the right relationship to be able to give candid feedback on your way out.
If you are faced with an exit interview, just smile and tell them how much you enjoyed your job. You can never get yourself in trouble that way.