A lot of things fall into the inconsiderate category, though most of the time I think the person being inconsiderate is too involved in whatever is going on in their life to even realize they've been rude. I know I've been guilty of the same, realizing later that my actions weren't very nice, or that I wasn't very kind. Stuff happens - we're either on the giving end of the crap, or the receiving end.
Then there are times when people are purposefully inconsiderate though they know they're crossing the line. They know. They know and yet they can't seem to stop themselves. Or maybe they don't care about stopping themselves because their needs are the only ones that matter and they don't care about you, or anyone else. They don't care. They just don't. Because what they want is more important and they're going to harass you until you finally give in or blow a gasket. And they don't care if you're pissy with them when you do give in, because ultimately, they've fulfilled their desire. If you blow a gasket, then they claim you have issues, or that you need to chill, or a dozen other things that basically put the blame on you. Because if you would have just given in at the beginning, none of this would have happened. It's your fault for not doing what they wanted when they wanted it.
Oh, why did I give up Moaning Monday?