This is probably mostly due to the fact that I hate the cold so much/am too lazy to do a thorough job scarping in the first place. Most of the time, I only seem to get a good one foot square to see through.
When I'm about 5 minutes from my house, the battle begins. I love when I can see a spot that I know is going to get knocked away by the next swipe of the wiper.
The really sad part is that I get a little sad and disappointed when the battle is over and there's nothing left for my wipers to do.