I end up putting villains in my stories even when I explicitly don't want to. ^^;
Like, "I'm going to write a sweet slice-of-life type novel, where it's mostly about just living life and overcoming your emotional baggage-- ACTUALLY there's an evil guy in the story who not only stalks the cast from the shadows for half the plot, but gets violently killed in the end...!"
"...How about a coming-of-age type novel, where a little princess goes on adventures and discovers who she wants to be-- ACTUALLY her friends have deceived her, sending her into the clutches of the evil yet beautiful tyrant prince from a far-off land!!"
"...Okay, well, how about this basic slice-of-life manga concept about kids just having fun and being goofy-- ACTUALLY, evil jealous boyfriend! EVIL JEALOUS BOYFRIEND "
...The third one, I'm still on the fence about, but I guarantee it's gonna happen. ^^; I can't help myself...
Villains really are a lot of fun, though, so I don't mind.
The visual aesthetic is definitely a big part of the appeal for me, but in all honesty it's not enough. I need a character who truly is villainous, not just one who looks the part.
I remember one concept in which I made up a non-evil character who was specifically and heavily villain-coded in appearance/personality, to try to satisfy the urge...only to later create an actually evil character to provide a dramatic final act to the plot. ¯_(ツ)_/¯ Gotta have the whole package.