My observations have two constants:
1. A two-lane, fast stretch of freeway (or highway) through rural/bush land, clear of obstruction and superb visibility.
2. Once I hit the freeway, I set the cruise control for 2km above the speed limit - so sue me - so that I stay out of the way of anyone else who either has no cruise control or has set their own control to the exact signed limit. It just annoys me less that way.
Disclaimer: I'm using the male gender here, for the most part, but realise that either sex can be equally guilty as charged.
The Stall Guy - you think he's stalled in the left lane. But no. Wait. He is actually moving. Like a snail. Even at the speed limit, you overtake this car - usually some sort of van (tinny vertical ladder attached to rear for ease of... climbing on roof...? optional) or clapped-out *insert vehicle model of choice here* - this one makes you feel like you're playing Need For Speed. Reeeeeally well.
The Slow Creeper - this guy is one of the most difficult to judge. His speed seems to wax and wane in your rear view mirror, edging ever closer to you but also remaining equally as far away. It's a mystery. He's like a goldfish that darts in and out of the same ruddy treasure chest. All day.
The Out-Of-Nowhere Bullet - one minute, the overtaking lane behind you is clear for use to pass the Stall Guy in front. The next, you are having to hot-tail yourself out of a road rage incident because he came up so friggen' fast on you that he SURELY created the Doppler effect. And no, he was certainly not there and you just missed him! This one is usually a business/on-road rep type. Guaranteed, he will be wearing a collared shirt and driving an executive car.
The Formation Driver - this one really takes the cake. This is the guy who sits just inside or just outside of your blind spot.... for miles. You'd alter your speed, but you're frankly too gobsmacked at the synchronized driving you are witnessing and want to see how far it will continue. For you are maintaining a constant speed of 2km above the speed limit, but then, Lo! He needs to make a move.... Riiiiight when you are coming up on a slow car in your lane. Fancy, what a coincidence. With this driver, every time you encounter him, you have to come off your set limit, which you would think would make him go past, but noooo... he matches you and stays in your blind spot! Genius!
The Defies Logic Nut - this one engages you in a bit of light flashing. This is the one who gives you a bit of a chortle as you're cruising past. You see, this is the one (ALWAYS, without exception) who thinks he is your father who knows better - err, complex, much?? *note to self: explore father issues* - and decides to reprimand you for overtaking him. No matter that he is doing 10 under the speed limit and you yourself are not speeding. You are overtaking! You blighter. And you'd better say sorry or you'll go to your room. This driver also, 99% of the time, has his wife in the passenger seat. And they are both well over 60. And drive a gold Camry (or other model, but always gold... or that lovely metallic green...)
So there you have it. I think I've covered them all.
Have you noticed any others? Do tell!