Today I did my first "watch what you're doing" honk. I was driving down the highway (luckily not minding my own business). You can see my car in the picture below as the brown car. The Other Car (silver oval) was doing a Michigan turn. (Side note: Michigan turns are weird left turns. Basically you take a right onto the highway and the do a U-turn around the median.) The other car was moving as I approached, but I wasn't thinking much about it. I figured they would scoot into the turn lane or into the right lane; it happens all the time.
But no. They slowly turn into the left lane. Slowly. By the time I realize that they're not being polite and that they aren't speeding up quickly I have to step on the brakes. Not super hard, but hard enough to topple the bag-of-stuff that I have in the back seat. Then I honked. It was a polite honk, but seriously...they really cut me off and there was no good reason. Then I had enough time to see no one was in the right lane (where slow cars are supposed to be), switched lanes, and continued on my merry way.