When it comes to the exit interview, DO NOT SAY ANYTHING EITHER. It all goes into your employment record. You don't owe them any honesty, so just leave quietly and don't burn any bridges.
Think of it this way, what do you have to gain by being honest? What do you have to lose? I think you'll see being anything other than polite and positive in your resignation letter offers nothing but downside.
I had one experience where I submitted a resignation (two weeks' notice) the same day as someone else in the company.
I said the bare minimum in my letter. When questioned by the CEO, division lead, and co-workers, I also said the bare minimum and kept it very neutral. The other person, on the other hand, decided this was their opportunity to express their anger and frustration.
As a result, their last two weeks were full of tense meetings, shouting matches, threats of lawsuit from both sides, and dirty things being said behind their back.
Meanwhile, my last two weeks were easy, stress-free, and nobody gave me a hard time. The CEO made me an offer to stay (which I declined), people were spreading positive things about me (I heard this through several trusted sources), and I generally left on a positive note.
The thing is, I felt the same anger and frustration as the other person. But as the parent said, I knew there was absolutely nothing to be gained by releasing any of it.
* Have a proper emergency fund (6-12 weeks). You should not be counting on any pay after you give notice.
* Have references outside of your immediate current manager
* On Friday, "today is my last day"
* Still be honest why you're leaving
Two weeks notice is a courtesy you're not required to extend to an employer (EDIT: This is US-centric advice, please verify this is true in your non-US jurisdiction), and you should only do so if you're on good terms.
"Reasonable" is up to you. As I said, notice is not (EDIT: as asked by other posters, this is US-centric advice. Please verify this applies in your jurisdiction) required. An employer is not required to provide you with any notice to terminate you, and therefore I only provide notice if I believe the work relationship will be amiable for the duration after I give notice.
Sometimes, you gain nothing from giving notice, and I refuse to allow fear ("hassle for employer", "coming back to haunt you") to drive my decisions.
(Here in Germany these things are a bit different anyways, default period is a month and can be longer by individual contract. Sometimes it is matched to the notice times the employer has to give, which go up to 7 months(!) for people that have been employed for a long time)
This is an international site, you should be careful giving out US "at will" state advice like it applies to everywhere.
In the UK for example, you can in theory be sued for failure to give a "reasonable" period of notice[0] (although in reality this nearly never happens).
That employee was foolish to stick around. At the first sign of hassle from the employer you scoop up your things and walk out the door. Your local labor laws cover you as far as making sure your last paycheck is delivered within a certain amount of time.
* how much you care about improving the company
* your relationship with the person to whom you are giving the feedback
* the interviewer's ability to effect change
But, if you trust the exit interviewer to both listen and possibly act on your feedback, feel free to give honest feedback during an interview. It's better to give constructive criticism ('the company could do better about communicating business challenges affecting comp') than to complain ('I'm leaving because even though we exceeded quota, my team didn't get any comp increases'). Just remember that because you aren't part of the team anymore, you have much less credibility than before.
I recently left a job and had an exit interview with the CEO (small company). I knew he could effect change, if convinced, and was trustworthy, so I offered some suggestions. I've left jobs with larger companies where the trust wasn't there, and didn't say much in the exit interview.
So your name, the fact that you are resigning, and your proposal for your last day.
And as others have said, when you submit that understand that your employer may ask you to leave immediately, so be ready to collect your stuff and walk out the door.
Maybe it should go without saying, but if you're leaving on good terms, it can't hurt to say nice things in your exit interview.