the feeling of not being understood by anyone and that the person is alone in the world. When in reality about a million other people are feeling the same thing.
Whining about how much your life "sucks" even though you live in the richest nation in the world and are a pampered little while [white?] boy/girl. Usually teenagers desplay this quality of "No one loves me or understands me".
A feeling of despair, anxiety, and depression. It is usually applied to a deep and essentially philosophical anxiety about the world in general or personal freedom.
a feeling of dread, anxiety, or anguish that is commonly associated with the teenage years. And angsty teenager tends to wallow in these feeling melodramatically, wanting pity from others while also simultaneously wishing to remain tragically misunderstood, much to the annoyance of his friends.
So as far as I understand it, people are angsty because they feel afraid but they can't put their finger on the cause, so the only way to react is being angry at each and everybody.
From my point of view, people are using 'angsty' to distance themselves from a problem that they have chosen to ignore. E.g. there are some problems with global warming, but even now, you can ignore them by telling yourself that it's teenage angst that makes people care about it.