What makes a Tumblr Sexyman a Tumblr Sexyman?

This question has been on my mind for a while now! Lately, i’ve been looking at what Tumblr considers a sexyman. But what about them makes them like that? I’ve seen most of the popular ones have top hats. Example: Alastor, The Onceler, Bill Cipher. But then I remember that there’s Sans, who had no top hat or skin in general. It might be their personality, but all of their personalities are completely different!! Black Hat and Sans are very different from each other. This question just keeps on confusing me the more I think about it!! But yeah, what are y’all’s thoughts opinions on this? I would love to hear them!! ^__^