When do you chose not to ride?

One thing I've been curious about are the times we chose not to ride. We can talk a good game... "I ride rain or shine!" "I don't care how cold it gets! As long as the roads are clear I ride!" But when do you make the choice not to ride?
As much as I enjoy going to a bar and riding my bike there I usually don't do it. One of my personal rules is that if I have anything to drink I'm not throwing a leg over my bike. Another time I make the choice not to ride is when I've not had enough sleep the night before. I am prone to the occassional panic attack and they will wake me out of a dead sleep. If that happens I'm driving the car to work.
I try to ride as much as I can (especially with a road trip to Indy coming up) but I also want to ride smart. I've been called a wuss for making the choice not to ride when everyone else did but I've never regretted making the choice.

When have you made the decision not to ride your bike? What do you think?