Headlight etiquette

This, I work with transports and we actually say thank you when cars let us pass. Also never get in front of a semi, we don't see you and honk if we slowly switch lanes and you're in they way. Sometimes people are in the blind spots and black cars are hard to see at night

One of my favorite parts about living in South Africa (besides sales tax being included on the price tag in the stores) was that it's common to flash your hazard lights to say "thanks" when someone gives you space to merge. I wish American drivers could do something like that.

I am in Texas, we turn on our hazards three blinks to say thanks for letting me pass you