It has partly to do with that most men buy terrible shoes. That's half the story. The other half is just that women like shoes the way geeks like digital toys

It has partly to do with that most men buy terrible shoes. That's half the story. The other half is just that women like shoes the way geeks like digital toys, so they always look at other women's shoes, and this carries over to looking at men's shoes as well. Because of this interest, women will always look at your shoes; you won't get away with an ugly or inappropriate pair of shoes. Men tend to underestimate the importance of shoes because they're out of sight, out of mind. Who cares what's way down there? So they don't pay attention and end up walking around with really god-awful or contextually inappropriate shoes which, to a woman's eye, jump right out in an unpleasant way.