I make at least a couple of lists every day. I love doing it with spreadsheets because I'm fascinated with formulas and equations. I take every opportunity to add numbers and calculations to everything, and the more complicated, the happier I am. I can spend days working on one list, or a series of related ones, just gathering information, categorizing it, and tweaking the numbers. The only problem is that I tend to do it at work and I get so focused on my list that, before I know it, the day is done and I have to go home but I never actually did any work-related work. So I have to work extra hard the next day to make up for it. I keep them all on a series of memory sticks, one for each type of subject.