(Disclaimer: not all of these I agree with.)

• Staring into an open fridge (while all cold air goes out)
• Using incandescent bulbs rather than CFLs
• Leaving the lights on when you leave the room
• Taking baths rather than showers
• Leaving cell phone plugged in, even when it is fully charged
• Leaving “vampire” electronics plugged in (electronics that draw power even when turned off)
• Not programming your thermostat
• Washing only partial loads of laundry or dishes
• Leaving the heat on when you leave the house
• Falling asleep with the TV on
• Not installing storm windows
• Not cleaning out air filters
• Leaving fans on in empty rooms
• Not using Energy Star efficient appliances