I have been tying my shoes the wrong way my whole life. It was thanks to HN that I found out, and it was mind-boggling. My knots were always untying, but I just thought that was the way they were, so I just kept tying them as hard as I could, to prevent them from untying.

This video explains it very well:

https://www.ted.com/talks/terry_moore_how_to_tie_your_shoes