?

It really depends on the story and the casting.

It depends on the movie. If the villain wins, does it mean no sequels?

It depends on whose motivations are clearly explained, and then what the motivations are. I rooted for Thanos in the latest Avengers movie.

It depends on the movie. As a kid l always pulled for the Frankenstein Monster, the Wolfman and Dracula. As an adult it still happens occasionally. In Kevin Costners version of Robin Hood, even though l know the story and how it ends , l was so pulling for the Sherrif of Nottingham.

Depends on how you define "Good Guy". In the fantasy story book Christians follow, the devil is painted as the "bad guy" and their petty, maleficent, super sky daddy Yahweh is the good guy. Never mind their god killing 227, 037% more people then Satan.

what type of mindset would root for the villain???

Pretty much depends on how the character's written. Is Jar Jar THE good guy? Wipe 'em out, Empire! Are we talking about No Country For Old Men or Needful things? I'm all about the bad guy. In the best movies, the sides are a little fuzzy. Case in point, the recent Planet of the Apes movies.

I like those movies where the good guy wins out and the bad guy gets his ass kicked within 2 hours. I think it was the law in America that the bad guy had to lose out in the end. They didn't want to encourage crime.

You have to decide for yourself it there's a good guy or not !

Usually the good guy but I tend to enjoy those movies most that twist so that I end up liking the bad guy. Depends on what makes the the bad guy bad.