Drove home last night (for reasons not related to weather or cycling), so I had to drive back in today. It had frosted pretty heavily.
Bike commuting reason n+1: you don't have to scrape your windshield, or your wife's.
Traffic was unexpectedly heavy this morning in a couple of spots. It takes me 40-45 minutes to bike in. I've driven between work and home in as little as 12 minutes, one way. Today, it took 23. Plus scraping time.
Bike commuting reason n+2: you know just how long it's going to take to get to work, and you can plan on it.
Any other off-beat or uncommon reasons you want to share?