Luckily, where I live, there aren't a whole lot of stupid bikers (more stupid bicyclists <college town>), but the ones who are stupid are REALLY stupid. Wheelies in between 70 MPH traffic doing over 100, Passing on the relatively narrow shoulders, Driving on sidewalks for blocks to avoid traffic and/or stoplights, Doing endo's up to multiple stoplights... The list goes on. And, it's sooooo much worse when Bikes Blues and BBQ comes around in the late summer.
I will second what DesQ27 said about the safe bikers out there, though. Thank you for being safe and responsible.