Maybe they were yelling encouragements?

I had a girlfriend who was a screamer.

You really cant be serious.

Yeah, the first few months that I was commuting, they startled me. These days practically nothing even bothers me. Cars can come right up next to me, gun their engine and lay on their horn, and I don't even flinch. The conditioning for not being scared extends beyond riding too; last summer at a reunion, my nephew snuck up behind me on a very hot day, and pressed a fresh-from-the-icebox, dripping wet ice-cold soda on the back of my neck while I was talking. He was pretty bugged that I didn't even pause in my talking. A few years ago I would have jumped out of my skin.

See rigleys comments. This is classical conditioning. Positive rewards are seeing cyclists jump, give finger, etc. Negative rewards are ignoring jerks. It's up to you which reward you give to the screaming stimulus. With a mirror, you can prepare for a null response and help distinquish the behavior.

Think of this as dog training and you'll be close to accurate.

When I was a kid in Chico riding my bike home from school people used to yell, throw things, jump out and try to kick you, etc. Now I ride out in the orchards foothills so I don't see many people, but I have to agree that this town has a lot of ****-brained morons. The other fun thing is when you get the dumb drivers who think that getting right behind you and following you is somehow better than just passing.

I haven't heard a single screamer since I started using my I-pod

It has been a very long time since I had a screamer. But the last one was a passenger. I caught up to the car, put my head right at the window opening and yelled very loud right into the guys ear. He jumped out of his skin. The car remained stopped as the driver and 2 other passengers were laughing at Mr. Screamer.

A coworker who bought a Prius a couple of years ago finds enormous joy out of sneaking up behind me and honking the horn (about once a week). I'll grant you it was pretty funy the first few times, but at this point the joke is very very old.

I'm a jumpy person by nature and screamers always seem to startle me, even if I see them hanging out their window and know what they are about to do. But its okay. I figure it is just another type of Karma transaction. I'll get mine later and someday the screamers will get theirs.

I think I'd tell them as much in a nice message across the hood of that Prius with an allen wrench from my multi-tool.

I did the same thing with a pair of steel toed combat boots when a car cut in front of me in a crosswalk. I might get myself a big old stick.

I like it

Not a problem here. I don't think anybody has screamed at me.

It happens to me almost every day. Makes me jump every single time...

Here in Miami, road rage capital of the world, there are screamers, but not that many because the don't want to roll down their windows and disrupt their air conditioned cuccoon, and they have been conditioned not to scream at other drivers because it frequently is met by gunfire.

So instead, Miami drivers just try to run you down. They pass you as closely as possible, then get in front of you and slam on the brakes, look right at you and then turn left in front of you making you brake and swerve, etc.

Almost prefer the screamer because at least you know there is a threat.

Last screamer that screamed at me got treated to an earful of compressed air horn, the kind used on construction sites to shut the site down if there's an accident.