Tying my shoelaces
My Dad taught me how to tie my shoelaces when I was about 4. I distinctly remember one day at primary school tying shoelaces for another girl. She didn't know how, and I was quite proud that I did. That's why I was quite shocked to learn a few months ago that I've been doing it wrong for 24 years.
I came across Ian's Shoelace Site (don't ask me how), and in particular this page that explains why my shoelaces would often come undone.
It turns out that I would tie my starting knot and the bow itself the same way - both left over right. If you know anything about knots, you'll know that if you tie a knot like that, you get an insecure granny knot instead of a secure reef knot.
The funny thing is I did know about tying knots correctly, but it just never ever occurred to me to apply that knowledge to tying my shoelaces. In fact I never really thought about why I had to re-tie my shoelaces a couple of times every day, I just accepted that as normal.
Anyway, if you're curious, the fix for badly tied laces is pretty simple: just reverse your starting knot and voila, your laces don't come undone anymore.