I used to give out quick toots but I now give out full blasts (1-2 seconds) for the constant stream of drivers who fail to start moving at red lights because they are too busy yapping or texting on their phones. This is especially true for short, left-turn arrows at busy intersections. If you're too stupid to pay attention at traffic lights, then you deserve to get honked at. [I often see, as a pedestrian, long gaps between cars getting started at new green lights because someone is too busy with their phone.]
Lane drifters get long honks, of course, because I seek to avoid getting sideswiped or worse. About a year ago, I nearly got run off the road at one intersection several times from cars in adjacent lanes. The problem was partly due to disappeared lane markings, which finally got repainted after I complained for months to the county's DPW. Then there was the idiot who decided to stop in a thru lane of a busy road, no signal, no 4-way flashers. He got a long honk, too.
As others have posted, I also despise drivers who nearly come to a stop, THEN put on their turn signal for the very SLOW turn they make. I sometimes honk at them, too.
EDIT: my 2-horn-blast story. One time, I had to give the woman in front of me TWO horn blasts because, after the first one (she failed to move at a green right-turn thru arrow), I saw her raise her hand in a "why are you honking at me?" motion. I gave her a second horn blast and she finally figured it out that she had the green light. She did raise her hand again in an "I'm sorry" mode.
