Do you tend to write for yourself? Do you ever think, 'Man, I want to see Harry defend Snape with some karate-inspired moves against a legion of the undead', and then sit down and write it?

I've often thought "I wish I could write, so I could finally read a story about blahblahblah". But I wonder if it actually works like that. Do you get the same satisfaction reading your own work than if someone else had thought of it and written it instead? Do you ever re-read your stories? If you know the end - because hey, you wrote it! - does it lessen the enjoyment?

I'm curious. =D