On my last road trip a tractor/trailer passed my and I dimmed my lights as it passed. When it was maybe 1/8th mile down the road I put them on high, and he fish-tailed the rear trailer and lost 15mph. When I passed him, he pulled into the left lane and either ran up on me or brighted his lights. I jinked into the right lane, an on-ramp and the shoulder. His horn bellowed in either rage or frustration—he couldn't touch me without overturning his rig. Never saw him again, he probably had a schedule to keep.
Assume all truck drivers are serial killers.
Edit: long-haul truck drivers.