I develop and memorise strategies for RTS games, particulary the very first few beginning seconds. I become paranoid if I lose any of those seconds. For instance, I have around 8 different strategies for the first moments of Forged Alliance. I will adopt one according to the playing conditions.
So, I may think "oh, I have a twenty-minute no rush on, therefore I'll use that to first build some essential resource gathering buidings. Four Mass Extractors, and then a Factory for mobile units. It can upgrade while I build power and upgrade the mass extractors..."
It will get to a point where I can predict how long stuff will take to build, the optimum order to queue stuff and how to make the most of a very little. I consistently use very few resources and units, have the smallest base, but out-class my opposition in quality. This is a game that can have up to 1000 units per player, yet I regularly use less than 250 units (buildings included).
I consider myself obssessive, and sometimes I don't even think it helps make me a better player. It just satisfies my obssessive need for economy.