I went to Stanfords in Covent Garden to pick up a 1:25000 OS map.  I don't usually go right into the beating heart of The West End but I took the precaution of taking a handful of baby-wipes in a ZipLok bag in case my chain dropped off again.  (I don't mind riding around Shepherd's Bush with fingers covered in black oil, but I figured the shop assistants in cool territory might be affronted).  Coming home down Charing Cross Road, there was red light at which I stopped and put my left foot down.....but it didn't land on top of the kerb as expected and I keeled over in glorious slowmotion onto the pavement with the bike on top of me.  I had barely hit the paving before five concerned young people (God Bless them) were upon me earnestly inquiring about my welfare.  It was all rather depressing.  FFS! Do I look 
that old???
Yes, the chain had fallen off, and yes, I needed the baby wipes, but my ego was in shreds.