It depends on where you live. It is really mellow here, compared to when I lived on the East Coast. I have not had a face-to-face or dangerous confrontation in a couple of years.
I'm sort of used to being buzzed, though, to the point where I don't really notice unless they swerve into the bike lane or off the shoulder of the road right in front of me. Most of these seem to be people not realizing how close they are until they are right beside me, and swerving over as they look at me in the rear-view-mirror to see if I noticed (usually worried or "Oh my!" looks).
About once per week someone does something passive-aggressive to "mess" with me. It is usually a small construction or delivery truck/van at a busy red light that has a bike lane. These people drive all day, and get a case of road rage now and then.
It is almost always a man that gets angry about how I get to pass them at a busy red light in the bike lane. Usually they just buzz me a little closer (door mirror whistling past your ear), and glare at me in the rear-view-mirror, but sometimes they yell things, or if they have a big diesel engine, downshifting right beside you and pushing out a big cloud of black smoke is really popular lately (usually accompanied by giving you the finger, or laughing at you in the mirror).