[quote=@Riffus Maximus]
I think that's exactly what makes the best villains. They know what they want, and what makes them villains is the ways they try get it. Doesn't matter to me if they have a "sob story" or they're just plain lunatics, it's better to have diversity in each villain's motive instead of everyone being "mwhahaha, I have the power, hence I have to rule over all". Heck, villains are the heroes of their own story. Some of them might think this is for a righteous cause.

I believe so far every character I've read leans more on the side of "doing what's best for their own interests and world" than just being plain homicidal. Not that it's a bad thing mind you. I also can appreciate the trope of a psychopathic maniac causing mass genocide just for the fun of it. 
[/quote]

I believe it depends on the [i]type[/i] of villain you are going for, and that's based entirely on the story.

But I feel that truly great villains, the ones who make you tense up and put fear into the hearts of even the greatest heroes are all shrouded in mystery,without a clear goal that the reader can see.

Cthulhu is so scary because he makes everyone go mad by [b]just existing[/b]. Chaos Gods in Warhammer are primal forces of nature, and whilst some of them might not be straight up malevolent (like Nurgle and at times Tzeentch) they are still very alien in their way of thinking and do not yield, whereas their compatriots like Khorne are straight up just the gods of brutal, merciless murder. Skulls for the skull throne, blood for the blood god.

Even recently in anime, such as Jingoku or Chainsaw Man we've seen villains with powers and motivations that define the normal human goals of why someone would become a villain. When a villain with a goal crests the hill, the hero shouldn't think "maybe I can reason with him", because that means a reasonable men, and reasonable men don't commit atrocities without being threatened. But unreasonable men do, and when THAT villain crests the hill, the heroes should think "This is it, either we all die, or we triumph today".

Of course, motivations are good, but being reasonable isn't. One of my favorite villains ever is the main antagonist of WAKFU. He is driven mad by grief and is ready to take the whole world down to get what he wants. Yes, we find out in the end that his goals and even means are very noble, but he is still very much about to game-end the entire world, just so he can put it back together. In a way he is much like Thanos, a noble goal driving someone mad. But at the end of the day, the heroes should know that a villain that can, and is willing to do such things is not someone that can be reasoned with, and someone whom they should fear rightfully so. 

I guess it's not a lack of motivation, per say, but rather it lacking any rhyme or rheason that makes a great villain. As long as the villain lacks sympathy (again, if that is the angle you are going for) and feels like staring into the cold, uncaring eyes of a predator, then that villain has my approval. I'd be pretty bummed out if we had a villain in this RP who wanted Chaos to revive their dead family and they are willing to do anything, or whatever. Big L, we've seen that a thousand times, think up something new, something bigger. The sky is literally the limit, our characters have a piece of the primordial evil, I think it's time to absolutely turn every plane we visit upside down, ad leave behind a trail of destruction and torment the likes of which our daddy Chaos would be proud of.

Plot Twist: At the end of the day we all just want him to say he's proud of us, and we're a gang of angst filled, daddy issue misfits :lol