Many things and I am still alive and unscathed despite all the sh-t I have put myself through. A couple of times regarding bookings I have booked a hotel for the wrong month - I have done that twice now. Once in Phoenix. When they tried to charge me for no show I said I could not pay for a room I did not use. They did not charge me.
I like to think that as I get older I get smarter, but that is not always the case. But life is fun whether I do stupid or not.
G