My pinto shetland Sassy (the one and only horse I have with significant amounts of white) has a goofy habit when she's turned out. She'll make one full clockwise circle of the pasture at full speed, then find the muddiest spot she can and plop down for a good roll. It's always the same routine too; turn her loose, run run run, roll, then go to eating. All of that white, sigh....
She's actually got a lot of wierd little behaviors. She has to be standing in the same place each time I catch her. I can only use HER halter, heaven forbid I grab the wrong one, or GASP, buy her a new one. I have to hold the halter and the lead the same exact way every single time I catch her, or she gets scared. (She was an abused rescue). She gets scared if I pick up her feet 'out of order', it must be LF, RF, RR, LR. Same for clipping. She's an eccentric little thing, and that's one of the things I really love about her.
My geldings habit is actually a vice; he cribs. With or without a collar. He will also roll when he sees me pushing the wheelbarrow full of hay. When lunging, he will make three circles, then buck, reverse, three more circles, buck, and then he's good to ride. Oh, and this one... to worm him, he wants his head turned waaay around facing his left hip, then he's an angel.
My little Ripple mare will pee everytime she comes back into her stall; doesn't matter if she's been out 10 hours or 10 minutes, she'll squeeze something out.
And dear Klipsie, the giant mare, will cow kick the wall between her stall and the tack/feed room while I'm mixing cereal. She does it every night, and yet it still makes my heart jump.
That just leaves Dizzy, who is still easy going, uncomplicated and sweet, but the terrible two's are just around the corner.