For one thing, she places all her expectations on others instead of taking responsibility for herself.
Instead of taking initiative, she complains bitterly that "the other person" didn't do what she expected them to do. Never mind that it was never the other person's responsibility, and often these expectations were unspoken.
And, since she knows how everyone else should live, and they rarely live "up" to her expectations, she is not only miserable about other people not carrying the weight of her responsibilities (in ways that disappoint her and add to the things she would have to do if they were to get done), but is also miserable about things that have no bearing on her life at all. Misery by proxy. Her entire existence seems wrapped up in being miserable and downright hateful because other people don't do as she expected them to do.
As I was once told by one of her relatives "Anger makes her happy". A rather "New Agey" (and therefore questionable) video I recently watched pointed out that some people are addicted to negative emotions and need to get that fix no matter what.
It illuminates a trap I now, being aware of it, strive to avoid. Amazing how much liberty you can gain when you let other people live their own lives, and when you take responsibility for the things that matter to you.