Once cats mature into adults, they can no longer process lactose like they did as kittens. This does not stop them from demanding or outright stealing dairy products.
For some reason, there is a lot of information on the interwebs saying not to do this because it is "too stimulating." Every single cat I have ever encountered has loved being petted on their butt right before their tail. The key is to start very gently, and if they want more, their butt will start raising in the air.
Cats are visual learners, and since they can't see where the toilet water goes when you flush the toilet, they assume it disappears from existence. They are genuinely afraid that you will get sucked into the toilet and vanish forever.
Cats are actually farsighted and have trouble seeing things close to their face, this is the reason why they can't find treats when you put them right in front of their face. In addition, sometimes they will wait to start eating because they expect you to take a share. When cats hunt and bring their prey back, they are entitled to the first bite. Since you are the one providing the treats, your cat may wait for you to take your share.
The number one rule when having more than one cat is that they will all expect to be treated equally no matter the situation. If something happens that indicates favoritism or discipline when the others don't receive the same treatment, then be prepared for the unexpected consequences, and they will punish either the cat or the human depending on how they perceive what happened. For example, Jaffa doesn't like tuna, Vinnie is allergic to tuna, but Maya is given tuna - Jaffa and Vinnie see this as unfair. To solve this, when I give Maya tuna, I give them special chicken treats that upset Maya's stomach so she doesn't get them but they do, and they are all happy.
We've all been so excited to be home with our cats and then they spend the whole day sleeping, yet if we leave the house they seem to go crazy not wanting us to leave, it's so confusing right? It's because when the cat parent is home, they feel like they are being guarded from predators and can actually go into a deeper sleep then when they're home alone. Vinnie wasn't in a shelter very long, but being in a cage all alone at night traumatized him so much that he will not sleep alone, and if he does accidentally fall asleep alone he will literally start screaming when he wakes up so he knows where the other cats or cat parent is and comes running.
Both cats and humans have dreams and nightmares. Cats will moan just like a human when they're having a bad dream. If you're nearby please gently wake them up and reassure them everything is all right. If they were sleeping elsewhere, they will most likely seek you out to get attention to make themselves feel better. To prevent scaring the pee out of my kitties before a planned loud noise, like vacuuming, I will gently wake them up so by the time I start vacuuming they are awake and can go hide.
Even though "good" and "bad" are abstract concepts for cats to grasp, the way you say the words to a cat makes all the difference and they will react accordingly. Building up the confidence of a new cat is so important, especially if their prior situation was horrible. Giving a cat praise after they do something well or make an attempt to do something can really make an impact. For example, all 3 of my cats came from shelters and had never really played with toys before. They were very hesitant at first, and if they didn't catch a toy they would just seem to give up. Praising them each time they tried to catch the toy made a huge difference, they were more confident, and after a while want to play more often and longer. Positive reinforcement can be used for so many things, and is very successful most of the time. Naturally, cats will do what they want, but they also want to make their cat parent happy.
After bringing a cat home, they are usually scared for a while. Getting down on the floor with them and seeing the world at floor level makes a huge difference, not only with their view of you, but also, how you see their world. Vinnie was terrified when we first brought him home, he immediately hid under the bed. I got down on the floor on all fours and waited for him to come out, then we walked around the house very slowly for over 2 hours (I was on all fours) while he checked everything out. After that, he was much more relaxed and not scared anymore!
Cats view their human cat parents as giant, hairless cats that just suck at being cats. They will put a lot of time and effort into showing and teaching humans how to do things, like grooming and catching prey. Our cats do see us as parental figures, so they meow at us and will do many things that a kitten would do with their mother or the other way around, either way they show us we're family.
Cats whether male or female will often times take care of a kitten or younger cat. Naturally the energy and playfulness of a kitten/young cat will annoy an older cat, but they will usually not want any harm to come to the little one (unless they are the ones doing it). Studies have actually shown that neutered male cats are gentler and calmer parents to a non-biological kitten/young cat than spayed female cats! Fun fact - Female cats that have been spayed can have symptoms like when they used to be in heat, but many years later, such as mood swings, aggression, and being vocal.
Cats are really humans in tiny fluffy bodies! They thrive on love, routine, sleep, food, and stimulation. Cats will learn routines fairly quickly, and if you change the routine, like setting an alarm for a different time in the morning, they will take quite a while to shift to the new time. If you disrupt the routine by not doing something they expect you to do at a certain time, then they will be quite "purrturbed" to say the least. By incorporating fairness into routines and changes to routines, cats will adapt better and be happier about it. For example, when it was just Maya and Jaffa, I would always pet Maya first because she was with us first and was older, which Jaffa was fine with because I always petted him right afterwards. When Vinnie came, that routine didn't work anymore, especially because he would literally demand all of my attention. I came up with a "closer to farther" rule - whichever cat was closest to me at that moment would get petted first, and I would go to the farther away cat next, making sure that all 3 cats go petted within a reasonable amount of time. As it seems like they're never in the same place or configuration twice, they all take turns being the first one to get petted. They agree this is fair and are usually "purrfectly" happy with it. Of course sometimes they will cheat to cut the line, like sitting directly in front of the bathroom door so I have to pet them as soon as I open it, but they will all take turns doing it so they've decided that it's fair between them.