Passing a full sized p/u on an Alberta two lane? 90% of the time, the driver will FLOOR it when you pass. Red-neck jerk-off a$$-hole driving tactic.
The trick is to be subtle, and then hammer it by them. Don't ease by. The instant you know you're passing, you have to have the pedal to the radiator. Yeah, it might mean doing 160 in a 90 or 100 zone to ensure you don't get caught out, and you're risking a ticket, but that beats repeated attempt to pass. After an aborted pass, the driver will back off to 80 again.
What else will these jerks do? On a multi-lane highway, if you're in the right lane, say, going 115 in the 110, and they're doing 120, they'll race up behind you and tailgate you, despite there being an empty left lane. Nice.