the how is they have toddler brain level intelligence, and at least for the first 4 years or so, they are inquisitive and their brains are very plastic.
my cat was about 6-8 months old when he came in off the street to dine on my offerings and it took about a week for him to start to forget about the nasty medicine regime the vet decreed for him. the regime worked to fix all of his health problems but at the end of it every time i open the fridge or cupboard to prepare a dose of medicine he scoots into a hard to get at part of the house and makes my job a lot more difficult because i have to reach in and grab him by the scruff of the neck and drag him out before i can put the goop in his mouth.
fortunately, that regime is over and even i started to just put the antibiotic in his food instead of directly in his mouth, and a bit over a week of this and he doesn't panic every time he hears me tampering with something in the fridge.
he's pretty much fine now, gingevitis is gone, recovered from the dental surgery and removal of a nasty lump in his mouth from it, his earache is finished and his eye infection is gone.
it was wearing having him have so much aversion to me during this time, and i'm so relieved i can just deal with his normal daily business of feeding and pats and cleaning his toilet.
they really are a lot like toddlers, and that's partly why they are so adorable and endearing and good company to have around, because that level of intelligence a house-mate is easy to get along with once you know all their tricks and preferences.
with the cat, the best part is he asks me to have the lap and then smooches and snuggles for as long as he can get away with and then he jumps off with little prompting when i'm too busy to give him that much time or he gets bored and the night routine is hilarious, he literally takes under 2 minutes to figure out i'm in bed and then up he scoots and it's smooches and he plops himself down usually between my torso and arm and purrs up a storm. then sometimes he sits and cleans for 10 minutes which is annoying, but he's started to learn that annoys me, and basically that he can get away with that if he gets away from me and sits in the corner to do his thing.
the important thing for the pet keeper is to recognise the pet can be taught enough to mostly take care of his needs except for cleaning the potty and dishing out the food. once you get into the groove with them it's all joy and simple duty.