Wind!
When you're outside with one foot clipped in the pedal and you're waiting for your Garmin to locate the satellite and the wind kicks in at 50-60 mph and you can barely keep control of the bike and yourself while you are standing, is it a good idea to go for a ride? Apparently the answer is no. I rode for about 2 minutes and turned around and I struggled to stay upright for the entire 2 minutes. I am pleased that I am getting wiser as I get older and I know when it's not a good idea to ride.
Specialized Amira Expert WSD, Ruby Expert
Trek Madone 5.2 WSD, Bontrager Affinity 2 WSD
Trek Madone 4.5 WSD, Bontrager Affinity 1 WSD