Lower your heating bills with an inaccurate digital thermostat. Pressing the 'up' button would always increase the displayed temperature, but randomly would not actually turn up the heat, so it would be reading a few degrees high. (Or low, in the case of AC.) You'll feel warmer simply because you turned
up the heat, even if the temperature didn't actually change.
Of course it should turn up for real some of the time, say 50-75%, as the effect won't work if you know it's not going to actually get any warmer. Your average room temperature would still be lowered, which translates to a lower energy bill.
Even if it doesn't fool you, the other people in the house who keep turning it way up wouldn't have to know a thing.