I will only do it if the left lane ends and someone is trying to drive to the end of the lane before merging and cutting everyone off who is being held up. In that case, the fast left lane driver can eat [censored] and end up in the median. If the lane doesn't end, I have no problem letting people pass me if they are going faster and intend to keep going faster.

"If you are flammable and have legs, you are never blocking a fire exit" -Mitch Hedberg