I've never understood something: If it's summertime and you want to cool off, you'll set the air conditioner at 68°. As such, I assume 68° is a comfortable temperature for you. Why then, in winter, do you set the heat at 74°? Haven't we already established that 68° falls within your comfort zone? And if 74° is suddenly comfortable, why can't the air conditioner be set there in the summer?
My roomates had similar climate control issues during my freshman year of college. Two of them liked the air to be cold enough to lure in walruses (one of them even claimed that he needed it that cold for his computer to run properly), while the other two of us preferred a more normal range.
Every day, the two roommates who lived on a steady diet of walrus fat and crushed ice (acually, it was more like chicken fingers and Dr. Pepper, but this makes for a better story) would knock the thermostat down to its lowest setting. Whenever my more sensible roommate or I found our environment in such a state, we'd knock the temperature right back in the other direction (that is, assuming our fingers had enough sensation left in them to actually feel the thermostat sometimes we had to put our mittens on first).
After a while, we got tired of this stupid game and decided to take drastic action. We opened up the thermostat casing and, with a pair of pliers, twisted the mercury-filled temperature gauge out of alignment. Our operation caused the thermostat to "think" the room temperature was in the mid-50's when actually it was somewhere in the low-70's. Now our foes could push the lever as low as it would go, and the temperature would end up right where we wanted it.
Unfortunately, I don't think such a procedure would work for me at home today.