True story: The morning before going in for foot surgery, my mom was in a silly mood and wrote “wrong foot” on the other non-surgery-scheduled foot with a marker before putting on her socks.
After the surgery everything was fine, and later when checking up on her the surgeon told her everyone in the operating room got a good laugh out of that “wrong foot” message.
Mom was glad her joke worked out, but later started wondering why they were looking at the wrong foot in the first place and now wonders if her private joke to amuse herself actually saved her from having the wrong foot operated upon.