And many times our memory deceives us or we subconsciously alter our stories in a way to suit our narration.
I actually had to face embarrassment once due to one similar incident. Being a hockey player in my school days I had a habit about bragging about one last minute goal I made in a final match which won us the district level cup. Once during a family gathering to which I had invited a friend over I started to narrate the same story after which my friend argued that such an event never happened at the mentioned game. After much debate (where a few calls were made) we all recalled that the goal which I kept on talking about was actually made in an intra-school match which was played few days before the cup final and I had some how confused the two into a single day.
After that incident my own family have doubted on every word I say and are never really sure of anything concerning me.