I get very angry when someone pulls out of a sidestreet or stops me when I am in a full speed run. But I try to keep it in. As others indicated there are alot of nuts out there. So I just stop if I have to, Speed up if I have to. As far as the honking of the horn I don't you should signal cyclists that way. There are billions of people out there. Getting mad and getting into confrontations isn't going to change anything. That person that just pulled out in front of you is the smallest of crumb. Go around the corner it's happening again. There is nothing to can do to control it. Luckily I enjoy being on my bike and it feels great after a nice long ride. So my anger goes quickly.