Ignorance, lack of respect and total self absorption.
Because they weren't brought up properly. Sometimes they're born to rude people and sometimes it's because they never received any discipline at home or at school. So they have absolutely no idea how to act decently. They have never mentally grown up, petty, undisciplined children in adult bodies.
It is the only time the have the guts to say anything, they are cowards. People that know them will put them in their place.
"When you are nothing when you are strange"Doors
They could be going through a difficult time and strangers could easily annoy them, I know that feeling. Or perhaps they have no interest in other people so they just shrug them off. There are many different possible answers to your question.
maybe they are having a bad day....or week. month. year. i go through my cycles, sometimes i feel like killing someone, then i go play gta on my ds lol.
I don't show respect to strangers unless it's warranted, but I'm also not rude unless it's warranted.
Because they are driving a BMW.