Tempting You to Stay. It's a reaction that's both good and bad: Your boss values you so much that he or she offers you a raise or promotion to stay. But it can leave you feeling conflicted: You have another great job lined up__but now that there's more money on the table, do you really want to leave your current position?
Sure, it may sit in the depths of HR until the end of time, but you can be sure of two things: One, your former boss (and future reference) will read it and be impressed. And two, if you ever decide to come back to your company (hey, it happens), it's a very good thing that last thing on file is a great, professionally written resignation letter.