Yeah and I do think the film does a good job of showing how scar ended up this way.
Mufasa is everything he's not (regal, physically imposing) and all of Scar's assets aren't valued in that society. He's living in a cave completely overshadowed by his older brother and he's powerless to do anything about it. His brother gets the crown, the girl .. everything.
Then along comes Mufasa's kid, and he's expected to be first in line to celebrate it. And the kid is a bit of a spoiled brat, flaunting the fact he's going to be king. It's no wonder scar ends up bitter and twisted!
Looking a bit too much in to a lion here , but I do genuinely think he's a really great villain in both movies, but in particular the live action style one he hits that balance of not being evil for the sake of it but a character you can understand, whilst also having genuine fear factor.