My, my; what a Question, It truly depends on who the villain (ness) is. Are they related to the character? Have they always been around manipulating from the sidelines? Or are they someone who has recently appeared? It also depends on the type of personality they have. Are they outgoing, possibly highly influential or are they
the type that hides and attacks when you back is turned.
Yes you have to give the villain some type of background without going to far, you also to consider are they misguided and will be redeemed in the end, or are they truly going to get what’s coming to them.
Each story has a different Hero/heroine so also each one has a different Villain/villainess as such it is only when the tale unfolds that you truly get to know all the characters involved.
I will always have to deal with evil and all around bad guys for the simple fact I write fantasy, if I ever branch out into other genres I may not even have a villain at all life itself is demanding enough, not too mention most of the hero’s are jerks we have to reform throughout the story.
So do I ever want to whip my bad guys, of course? They wouldn’t be bad...