We have a front door and an inner porch door. Every single time DH goes out to put the rubbish out, get the milk, go to the car etc. he leaves both doors open.
The freezing draught blows straight down the hallway into the kitchen and results in me shouting like a mad old woman 'Can you close the f*ing door please, you're letting all the heat out!' or 'Were you born in a barn??'.