One of our cats, who passed away a few years back at the grand old age of 18, had three very odd habits.
She was addicted to licking men's armpits! LOL Sounds freaky I know but she would not leave men alone, especially in the summertime and especially if they slept in a position where she could get to their armpits. I don't know if it was some sort of over blown grooming reflex or she just liked the taste of sweaty pits but we really never did break her of it.
She had that same sort of nursing thing too. From the time she was a kitten she would attach herself to a certain bathrobe I had and starting madly nursing and doing that paw kneading thing on it. Not much fun to be trying to drink your morning coffee and you've got the crazy cat attached to you LOL. Eventually she literally ruined my nice bathrobe. I made sure when I replaced it to pick another material and she completely stopped the habit. I think something about the fabric must have felt like her momma.
Her last funny habit was what we called "crazy hour". She's be just laying around, doing nothing then suddenly bolt upright, glare around in a very hyper state and take off at a full run. She's literally bounce off furniture, scatter newspaper, vault on to and over the dog...it was hilarious! Then as suddenly as it started, she'd stop, groom herself and have a nap. She did this pretty much from her kittenhood well past 10 years of age and only stopped it when she literally became too old to move quite that fast.
She was my best furry friend. I miss her still. She's been gone a long time now and I've yet to feel right about getting another cat in the house.