Is it time to start calling out bad cyclists?

The other day I passed a guy who decided to sit on my wheel. Half a mile later, on the approach to a roundabout he decided to overtake me and because he was now going too fast, and the cars ahead were braking, he had to swerve into my path, almost taking out my front wheel.
I called him out but he just looked at me blankly, then again switched into my (left turning) lane and turned left in front of me. I asked him what he was playing at but got more blank stares.
I turned off later on and he then bellowed some abuse at me. I decided to go after him and give him some advice, and I caught him a bit further down the road, which caught him by surprise, and pointed out the error of his ways. He accepted a telling off and we parted.
Tonight he pulled over next to me at some lights, offered me his hand and apologised quite genuinely.

Nice. Riding a bike is a social skill.