Old one for me, but as a kid walking home with friends from school, I realised there might be a better route that would significantly shorten my walk and make little difference to them. I mentioned it and was fobbed off. So later I pulled up the route online and actually measured it. Not only was my suggestion a better route for me, but it was actually shorter for everyone else too! I triumphantly took my findings to my friends who to my surprise and disappointment really could not care less, and a little part of me died because they were not my friends.