You've hit the nail on the head. I'm a mixture of hobbyist and compulsive problem solver. I tend to lose interest fairly quickly in stuff that I or someone else doesn't use.

My largest project was only started and still exists because my friends and I had a need. It is now used daily and I'm still strongly developing it and adding new features. It's great; 97% of the time, seeing people use my stuff is what drives me to code.