I am an ex-runner. I am new to cycling and vowed never to be that person that delayed traffic, so I am not that far removed from thinking that cyclists are a pain in the ass. I have never cursed or honked, but I have thought been very annoyed.
I have "seen the light".
Now, I ride in to work a couple days a week (10 miles each way). I smile and wave to people who yeild the right-of-way. It is my job to increase awareness and each time I am on the bicycle, I am an ambassador for cycling. We all are. We can flip people off or throw things or try to fight drivers all day, but it does nothing more that make it difficult for yourself and everyone else in the long run.