Looking through the Looking Glass: Exercise

My exercises usually are non traditional. This one is going to be strange as well. I've heard the write a letter to hour character, or from one character to another idea, and I don't like it. Instead to flush out a characters fears and motivations, write a letter from them to you as if they just found out that they were imaginary. Do they feel bad? Betrayed? I'm sure they are upset that they were put through a particular thing or that they weren't, and that's your fault.