Suppose you have been with a lover for a while, but that he or she decides to break off the relationship. Because of the contrast effect, there is an initial reaction of grief. You may then observe your mind play the following trick on you: To reduce the pain of separation, you redescribe your lover to yourself so that he or she appears much less attractive. This, obviously, is a case of sour grapes, or adaptive preference formation. You then notice, however, that the endowment effect is also affected. By degrading the other, you can no longer enjoy the memory of the good times you had together. In fact, you will feel like a fool thinking back on the relationship you had with an unworthy person. To restore the good memories you have to upvalue the other, but then of course the grief hits you again.
Jon Elster, Alchemies of the Mind: Rationality and the Emotions, Cambridge, 1999, pp. 32-33