All my life, I was tying the knot “wrong side up”, so it was untying. I was checking out a videonon how to tie high boots the easiest way, and the problem was mentioned. Now nothing ever happens to them.
It’s hard to explain in details, so here’s a quick check if your shoes are untying themselves. When you start tying, you hold two loops in your hands and cross them, putting one above the other, right? Well, this time, put them the other way around (left on right if it was right on left), and finish the same way you always did it.
You will immediately feel that the knot is not slipping. This is because you also do the first simple knot in a certain way, and first and the main knot has to be different relative to each other