The nice thing about commuting is that in the afternoon, you're already on your bike. You don't have to go straight home.

My commute is 5 miles. I rarely (not even 1/week) go straight home. My shortest alternate route is about 8 miles. It's not unusual to do 18-25 if I have time. I love hauling ass at over 30 mph in my velomobile. The looks I get are great. I can push that kind of speed for 3 miles or so before I have to dial it back a bit.