I just realized why I can never get to sleep at night: my extreme temperature sensitivity. Most (if not all) modern air conditioning systems alternate their on time according to the air temperature in the house. I tend to get comfortable to a certain setting of whether the AC is on or off. When it switches, I cease getting comfortable, and I turn. This process continues until I get so tired that I don’t care, or until I find the magic sweet spot that is comfortable in both settings (unlikely).