It's probably the fact that you're idling the car for extended periods of time. Long periods of idling is one of the worst ways to warm up an engine. Since there is no load (aka having to move the car) on the engine, it's very difficult for the engine to reach operating temperature.
When the engine is cold more fuel is forced in to help 'speed' the warming process. It probably stinks in your car because your engine is getting a ****-ton of gas to get it warmed up, and also catalytic convertor is taking on a lot of unburnt gas which will ruin it real quick.
Moral of the story, don't idle your car for a long time. Turn it on, scrape your windows or something and then take it easy driving until the car reaches operating temp. I said that idling for long periods of time is one of the worst ways to warm your car up, probably THE worst is revving the **** out of your car before it reaches operating temp (not just in the winter, either). Keep the revs under 4k before the car is nice and warmed up