Oh, and one thing to keep in mind is that motivation follows action. Just do something (or in your case, stop doing something) for a while and you'll start to enjoy it.
I have really trouble starting and stopping things. One helpful trick is just tell myself that I can work on x for five minutes. The other part of the truck is that you have to mean it. Sometimes I get on the computer to work on a side project, and then goof off on other stuff and some nights I’m working right up until bedtime.