It's not like I have a choice here. Besides, the building charges an aggregate heating cost per year that I can't really influence with my behavior other than not turning on the heat when I don't need it. With my downstairs neighbors, I end up having to open the window as well to get the temperature in my bedroom to reasonably low levels.
Man, I have a similar problem whenever I visit my parents: my mother is after a heart attack, her blood flow is impaired so she's always cold, even when there's like 27 Celsius degrees in the room. The first thing I do when I the house is to shut down the heater in my bedroom. The whole house feels like a sauna.
With a sufficiently insulated apartment, you actually stay at reasonable temperatures from other sources of heat: bodies, bathing, appliances, cooking, computers, etc. A normal apartment uses a couple kilowatts of power, which generates as much heat as a couple space heaters running all the time.
Of course having more effective insulation is a good thing, but that's not the case we're talking about here: were talking about "staying at reasonable temperatures" thanks to your neighbors.
If everyone is content with a lower temperature, they still end up heating less, and energy is haved. (Also, they are probably transferring much more heat from their own single heated room than from neighbors through walls).
So you're basically stealing the heat from your neighbors :) You can see how that strategy falls apart if everyone starts doing it?