I created a similar thread to this years ago and found it fascinating so thought I'd restart a new one:)
The strangest one for me is still the one I wrote about last time: I bumped into a former colleague who I worked with many years ago. When I told him I had two children he said ah yes, I remember when you were pregnant in the office. Except I fell pregnant years after I left the place where we worked together. However he distinctly remembered my pregnancy, the baby gifts colleagues got for me and the 'baby shower' lunch I had. He rememberd signing a congratulations card for me.
He remained absolutely convinced even when I pointed out my eldest's childs age didn't match up with the time I worked there and seemed to think I simply forgot when I left
There was no-one else in our office who looked remotely like me and no other pregancies he could have confused me with as it was a male dominated office.
Still puzzles me to this day!