If it's something that isn't that important than laziness generally wins over shoveling snow and cleaning off the car and whatever else is going on that would make me not want to drive. If it's just rainy or windy then smurf it, I don't care and I'll go anyway.

If something's important though, I will, and have, driven in pretty much anything. A few years back I drove me, my wife, parents and sister home from my grandmothers after Christmas. It's typically a 5 hour drive or so when you can actually do 110-120 on the highway. It started snowing when we left though and we made it through about the first hour before it started to hamper our progress. Spent at least an extra 2-3 hours on the road, driving about 50km/h through a blizzard for most of it because you literally could not go faster and without starting to slide (assuming you had the traction to speed up at all). It really wasn't that bad though aside from the visibility. It just took a lot longer. I didn't even really have to worry about other drivers causing problems because by the third hour I don't think we saw another car on the highway.