I've posted this before, but Jack does this a lot:

I love the picture. Is she a seal, or a turkey?

Our current cat, Tails, is scared of most everything. If something moves absolutely wrong, he will startle and look at it for a minute, then go back to his business. This includes us walking, open up boxes, curtains, and sometimes, cooking.
The same cat didn't jump when I accidentally dropped the Wii Balance Board with a huge KERBOOM. He just went on his business.

He also loves fighting tape. Loose tape hanging off an Amazon box? He's beating it up. Yes, we make sure he doesn't eat any, but...
Andy, our most recently gone cat, loved, LOVED, L-O-V-E-D catnip. I mean, most cats would be happy with their casual highs, we came home once to see a cat happily sitting in a double trayed, cardboard cat scratcher, one of the scratching parts ontop of his head, the rest of him laying in the bottom of the box with the herbs, practically green from the catnip he managed to get to.
He once spent a week in a REALLY GOOD mood. We were all puzzled, until we looked beside the bookshelf and saw he not only knocked off the bag of catnip, by climbing on the couch next to it, he ripped the bag open and he was rolling in it. Catnip got moved to a safer location.

Callie, Andy's long gone sister, loved to nurse. Cat licking your arm and kneeding kitty biscuits into it was hardly good for skin.

I hear its a neurotic behavior from being weaned too early, but...