Pump up the volume

I could complain about this forever, but I don't want to sound too old or bitter...

Seriously, what is going on with the decibel levels emitted by regular, every day people? On the street at traffic lights, on the train, in restaurants, in the apartment above me... people talking somehow manages to be louder than traffic, television, music on my iPod. I don't understand how two people sitting or standing within a few feet of each other need to speak so loudly that (a) they are pretty much shouting already and (b) they don't realise that the rest of the planet can hear them.

Sometimes, I'm quite tempted to pay attention for 2 minutes (I wouldn't call it eavesdropping, since they are the ones yelling into my ear canal), and then join in the conversation, amazing them by "you know, like, totally, OMG, yeah" understanding what they were going on about.

Most times though, I have to restrain myself from finding the nearest large, blunt object...