Always.
I'm no LL squatter, and sometimes when I gotta drive expedited have to go around them.
Often those squatters are trucks who think they own that lane.
They usually won't move over for a speedy Prius. ;)

I was referring only to those traffic jams that are many miles long and nobody is going nowhere.
People can either flip out, use up gas and brakes and ruin everyone's day, or they can just go with the flow.

Upside down from freaky iPhone?

Wonder why...