Has being absent of your glasses/contacts ever led you to do something really foolish and embarassing?

A few years ago I was walking along to the shops with my friends and in the distance I saw -what turned out to be a man standing on top of a truck slightly hidden by trees- a giant! So I turned to my friends and said "Oh my God! Please tell me you see that. That's man's a GIANT!" needless to say they did not let me forget this for many many months.

I also nearly walked right past my friends they other day when they were standing outside the school hall for an exam...I couldn't see them, I'm so blind. :(