Why?

I was on my way back from jamming with a drummer (He's done drums for a couple of the metal tracks I have uploaded), and as I'm pulling up behind this guy in the left turning lane (Nothing in front of him) he slams on his brakes, and screeches to a stop, forcing me to almost swerve off the god damn road to avoid him... I manage to screech to a stop before that's necessary, then he gives me the finger and pulls over to the side of the road like he expected me to get out of my car and come fight him...

What the fuck is wrong with people these days? I wasn't behind him until I was near the lights, so it's not like he'd be mad for me tailgating him as I just got there... So that leads me to believe the fucking douche did it just to provoke me... Of course it didn't work... It pissed me off to no end, but that low life wouldn't be worth my time... if I'm gonna get out of my car to kick the shit out of someone, it's gonna be over more than someone trying (and failing) to get me to rear end them.

But still... what the hell is wrong with people?

Part of me thinks it was my ex-best friend... he's a fucking terrible driver, so I wouldn't be surprised if he was in a rental... And he's immature enough that I could see him pulling a stunt like that... I didn't manage to get a look at them as I drove by, so I'm not positive, but that would make more sense than some random guy pulling that stunt... I did however return their finger as I passed.