Angst doesn't stand for character development. Angst doesn't even stand for characterization. If anything, angst will sometimes hinder development and freeze your character in time, keeping him/her from moving on and changing. I have very little patience for people who moan and wail and groan in online posts how miserable, how wretched, how pained, or how depressed they are -- so I don't go near them and refrain from making a comment, because these people generally crave attention and pats on the back. It's childish and pitiful; I've seen a woman who does it in spite of being over twenty (and should, really, know better). The minute I see a similar exercise from a fictional character, I snap and either stop reading or hurl the book across the room.
I've said it before in a different situation, and I'll say it again: nobody bloody cares. Especially in fantasy/sci-fi/adventure novels. Who really gives a damn about the heroine's self-esteem issues when there's a world to be saved, or there's a tyrant to be overthrown? Who would have the time? There's no way for the heroine to spend chapter after chapter moaning about the crush who spurned her ten years ago and not grate on a sane person's nerves. Now, angst can be done well, but excessive angst is never good. It makes me -- and a good many people -- want to slap the character upside the head and snarl, "Get over it already, you little brat!" Because, quite simply, misplaced priorities of characters lead to them angsting over every tiny little thing when they should have been able to come to grips with it and moved on long ago. Or at least seen the local equivalent of psychiatrist about it. Having another character yell at the bundle of angst to snap out of it is probably a good idea, too.
Worse still, many authors seem to think that it will garner sympathy and therefore attachment for the characters. Clue: it doesn't, not until you've made the reader care about the character first. Then the angst can have dramatic impact; if you're good, it'll tug at the reader's heartstrings. If you aren't, well, it'll just come off as cheap, gratuitous, and shallow. This brings me to the next point -- excessive angst lacks subtlety. Spare me the 4,000 words of stream-of-consciousness where the character just sits there does nothing but wallow in self-pity/guilt/pain, please. Good angst should be subtle and inserted between the lines, hidden under an ongoing, ever-moving story, not shoved down the reader's throat in a massive block paragraph. See R.A. Salvatore for an example of hideous, juvenile angst in the journal entries of his drow ranger.