If You Want to Do More Than Just the Basics with Your Resignation Letter. You can always write more, and craft a longer resignation letter, but the truth is that it isn't necessary. You can add a portion of the note where you thank your manager or boss for the opportunities and time you have had together, or add that you hope to keep in touch, but in reality, if you really feel this way you probably should make an effort and find an opportunity to say these things in person (rather than getting an email).
Spot the Signs. Again, you may receive this response if you have specialized knowledge that would make it difficult or time_consuming to hire your replacement__or if it would be helpful for you to be actively involved in that search.