Listen, guy beside me on the bus...if you want private transport, take a cab.
I get seriously annoyed at seat hogs. Not people who need more than their share--as a person of a certain size, I understand that Metro seats designed in Italy don't necessarily fit American-sized butts. What irritates me are people who stake their claim on 2 seats, refuse to move over, keep their bag on the seat even after you sit and even with a full bus or train.
This points to a general annoyance..a feeling of entitlement. In my estimation, it's why so many drive in the left lane even when not passing.
There's actually a great website exposing that crime against humanity...I'll link to it here when I'm not "mobile."