I know I'm going to sound really old...
...but the volume some of today's youth have their personal stereos (told you I was going to sound really old) set to is unbelievable.
Often it is so loud that I can identify the track from several seats along in a moving train. If they're near me, and I recognise the tune, I will start silently mouthing the words. This has even succeeded in getting the volume turned down a few times.
There was a girl the other day who couldn't have been out of her teens who was sitting next to me on the train. The volume sounded perfect if the ear buds had been in my ears, but they weren't, they were in hers! She's going to be deaf as a post before she's 30, if she's not already.
Although the annoyance of loud headphones is nothing compared to those who sit on a train listening to music on their phone via the speaker! With all the frequencies from 500Hz to 3Khz rendered perfectly, and the others lost to the world! Is their hearing that bad that they can't hear how terrible music from an 8mm speaker sounds?
And it's always complete crap too!