Rolling back and forth: Your cat is showing submission or inviting you play.
Making squinty eyes: Cats squint when they're content. Closing their eyes slowly is a sign of trust.
Sticking a raised butt in your face: Tail sniffing is normal in the cat world, so this is your cats way of saying hello.
Sleeping in a circle: It conserves body heat.
Kneading: This is likely a leftover trait from when they were a kitten when they did this to their mother's stomach to produce milk.
Sitting like a cat loaf: Cats tuck their paws under them when they feel safe, and it also conserves body heat.
One leg extended: This just makes it easier for your cat to clean.
Exposing it's belly: It's a sign of trust.
Nowhere to be found: Cats are good at hiding, and they're tired of your shit.
Staring into space: Cats have keen senses, so they probably saw a fly or a speck of dust.
Sleeping in boxes: Cat's find security in confined spaces.
The “hug ‘n’ bite”: Biting while wrestling is just part of how cats play.
Chirping or clacking at birds outside: That chattering is a reflex in anticipation of hunting.
Sitting on your computer: Cats like warm places. Also they want to annoy you.
The ready to pounce quivering butt: Cats wiggle back and forth to position themselves for the perfect attack.