Kids have always been brats, simply because they're kids. People have been complaining about kids being brats since the dawn of human history. I bet cavemen huddled around the communal fire complaining about how all the caveteens are little brats these days.
It's actually the fashion among young guys to wear one jeans hanging down below the arse cheeks. No idea why, but it's true. A lot of teenagers have a natural attitude then you get others than verbally abuse people on the street. Which is wrong those that do that are immature, and well the brain doesn't fully mature until the age of 25. So they don't have metal disorders. They are probably waiting for that person to turn around and confront or say something back. That's what them guys are trying to do provoke people to either get in a fight or get a rise out of them. Best to ignore it act like they aren't there.