Valassis-Durham, NC

Also, shipper knows you've got the ball and bat in your hand until you sign the BOL.
You can tell him you're leaving if you're being held up or you can tell him to unload it.
I know that often will hurt the trucker, since now he has to look for another load and may sit, but it's still better than the case with the receiver.

With the receiver, he knows you're at a disadvantage until he signs your BOL. Not to say there are no alternatives, but the bat in your hand is not quite as big as it is at the shipper.
I also firmly believe in going to the office, calling a supervisor or the home office of the company and reporting on bad behavior of rude employees. I told one office lady about a jerk on the forklift outside and said, "Mam, how do you get truckers in here to pick up your freight with a guy like him that treats us like crap?" Had to explain the whole thing to her. Felt good getting it off my chest.