I learned that below 0F riding isn't scary, overdressing and getting sweaty is scary, and a little bit of creativity can go a long way toward arriving with all parts intact. I also learned that I need an upgraded winter bike with proper studded tires before November (the last one got left in California).
Now that the snow has melted, I've learned that I am one of those crazy people who really, really loves the winter, and for that reason, I probably can't ever leave the Midwest again!