In the comics she has a lot of shit going on. She was 16 when Krypton blew up and was put into hyper sleep before drifting through space. When she woke up her cousin is now older than her and sanctimonious as fuck. She is basically alone and is doing her best and pushing all this down to emulate her cousin and be the role model he established.

She then meets her alternate self in Powergirl and she sees what she could be if she was herself. A whole universe of people started saying "Kara this isn't you" when it really is her finally getting to act like herself. She has a breakdown, joins the Red Lantern Corps, and basically becomes the strongest thing in DC for a few issues. She's incredible.

The apathy is a cool side to see and a side of her that is totally present but never shown. James Gunn is taking some real chances portraying the characters from the comics and not just pop culture echoes.

I haven't followed DC at all, but I suppose it could be a character growth thing through the movie? Or they just got bored with the happy little white girl saving the world, and moving more in the ke$ha direction? Either way, it sound more interresting to me.

I enjoyed her in Super Hero Girls where she came across as more annoyed that she had to do anything rather than apathetic. I know it was a kids cartoon but it was still good. I fear this movie will instead showcase her as an apathetic shit head who doesn't care about anything until big moment or love interest etc occurs and then she'll learn her lesson yada yada.

Hollywood can be so boringly predictable it makes me apathetic myself.

Maybe this is the movie where she learns to take passion in her work and becomes the enthusiastic superhero you know.

Eh, there have been, like, 4 different Supergirls, and they're all different. Silver age Supergirl is basically just Superman, but a girl. Post-crisis Supergirl is an artificial life form from a pocket universe or something (I forget her whole deal, but she's the worst one). Powergirl is Clark's cousin, but she's from another universe, shows a lot of cleavage, and her weakness is wood.

In 2004, they brought back the classic, "cousin," backstory, but this time changed it so she's a teenager sent to take care of baby Clark, but thanks to a suspended animation mishap, she arrived on Earth when he was in his 30s. Some writers have tried making this version a little more cynical, which makes sense; unlike Clark, she remembers life on Krypton and sees how primitive Earth is in comparison. It's like one those stories where a high-schooler is bitter because their parents moved them from the big city to a podunk town. It's basically Space Footloose, and Supergirl is Space Kevin Bacon.

I have seen more than one animated films where she is initially a brat and/or just a bitter teen

She winds up (through bad attitude and manipulation as well) as one of the Furies working for Darkside so this "take" is not entirely out of canon