In fact, many people know this, because "shoes" and "evil" are homophonic. If you send shoes to a friend, it implies sending evil spirits to the other party. First of all, I care about not getting it. Secondly, according to Feng Shui, this will lead to the frequent breakdown of their friendship. However, it is not a big problem to send shoes to relatives and family.
I hope I can help you, and I hope to adopt it!