I ignore 'em and shrug it off. During Tuesday's ride a car drifted into my lane on the curve leading toward the local MUP trail head. The driver honked at me, apparently thinking I got too close, instead of realizing he/she was a poor driver and was drifting out of the lane. I just shrugged it off and kept going.
I do run video for traffic documentary stuff but unless it's really egregious I don't bother reporting it. Maybe twice in a year, once when a car was driving the wrong way toward me in the bike lane (yeah, kinda weird), another time when a Domino's delivery driver nearly clipped me on a turn. Police couldn't do anything specific in the first case because the car didn't have a front license plate -- although they have increased drive time monitoring of that road. In the second case I was satisfied with Domino's corporate safety office response, and that of the local shop's manager.