this thread is to be about which pet behavior we have our sims reinforce.

me; following behavior categories: Calm, Clean, Housebroken, Playful, Respectful.

It is not like there is a huge list to pick and choose from.
Most of the time, I'll do like everyone else and reinforce the ones that makes a pet more pleasant to have., so the ones you mentioned.
Though I love to have pets eating from plates, my real pets love everything I cook. I also love to have all my 6 cats on my bed, sleeping with me.
So this is also something I'll let happen in the game.

I'm into opposites right now. So Bridget will tell the dog to be calm, but when her back is turned, Martha the room mate will have dog running crazy and howling. I want to see if it makes their personalities (dog) more unique. I'm also gonna see if the woodcutter (toymaker idiot) can make himself an attack dog.

That is a good idea.

I usually always get a pet dog or cat with the description of being a genius / smart I like them to learn behaviors fast. With the smart pet you don't have to go over and over of what you need to teach them.
Once they learn what not to do and what is right to do they are fine, Sims 2 gave our pets 6 personality that greatly impact their choices and behavior;

Genius / Normal /Doofus
Hyper / Normal / Lazy
Independent / Normal / Friendly
Aggressive / Normal / Cowardly
Pigpen / Normal / Finicky

I have try most of the different personality over the years I have found the Doofus pet is kind of hard to learn ( not so smart ) so it take patience, And the independent type of pet is stubborn and hardheaded want to do their own thing.
My poor Cowardly pet always got beat up by neighborhood strays ( lol ) and the Lazy pet was just that lazy, and the Finicky pet they want everything perfect and will not eat out of a dirty dish, the aggressive pet can be mean and growl at everyone.

I always house-train them, because it feels wrong not to, but it's really no better having them pee on the pavement than having them pee in the house. By the time Malcolm and Florence Landgraab get home from work, they have to wade through the most enormous puddle of pee right in front of their door, since their three dogs have all decided that 'just outside' is outside. Porthos always goes by the letterbox, which must really annoy the walk-bys!

I also teach them to behave in the tub, to save myself having to send a Sim to wash them multiple times in one day, and to eat pet food. And of course I teach them not to chew furniture, except that if a dog eats a child's homework, I let the child praise it.

One thing that annoys me is that kitchen counters and sofas are treated the same way; I don't mind a cat on the sofa, but I don't want it on the kitchen counter (especially the Tinkers' cat, who almost never washes himself and is usually trailing a green stink! Eeuw!).

I had a dog that was trained to be hostile, I didn't see much difference.

Weird, BlueAlien, my dogs always go for trees, flowers, or shrubs.

It depends on what's convenient for the sim owners. If it's an outdoor dog, I won't worry about training it to pee outside, because where else can it pee? (Though it may end up trained anyway, because someone rolled a want to praise it and that was what it could be praised for.)

Some families care about pets on furniture, some don't. If they have not enough sitting/sleeping spaces, then the pet needs to learn to stay off. If it's just a matter of three sims and a dog, and they have five seats by the bookcase, they don't care, so I don't care, if the pet is taking one up.

I'm anti-puddles-inside, anti-chewed furniture, anti-stink, and anti-refusing-to-eat-pet-food. Of course, some dogs (looking at you, Danny!) are kept kenneled, so training is less important, as, well, there's no sim furniture, no going indoors, no sim food . . . so that's how I handle the atrociously untrained/mistrained pre-made pets. Some sims prefer hostile pets: Consort Capp wants his rottweilers as hostile as they can be.

I made my actual real life pets in the Sims, and I am trying to train them to not destroy the furniture, because they've managed to destroy 2 sofas and a double bed at this point. I don't mind them going on the furniture because my actual real life pets do that (though it's ridiculous your sim can't sleep on their bed when there is a tiny dog on the end) and I don't care about them running around crazy (because my actual pets are completely insane except one of them, who is terrified of everything) but I don't want them to be aggressive (though it does fit one of my pets half the time, the other half she's lovely).

This isn't related much, but it's ridiculous you can't make puppies and kittens in CAS. My kitten is bigger than my dogs in the game which definitely isn't right...

Child age sims can share a single bed with a pet. http://modthesims.info/d/407570

@MasterRed You can make puppy and kittens with Christionlov's baby pet maker. Post #15 in the archive. http://www.modthesims.info/showthread.php?t=472257

Assuming that I remember this correctly, training the dog to be hostile means you can command it to attack sims you don't like (burglars, trash can kickers, etc.) I think most of the behaviors work that way - raising or lowering the meter all the way unlocks an associated command. ("Eat Pet Food" unlocks "Go eat", housebreaking unlocks "Go pee", etc.)

No, but I wish they could! pets trained to be hostile are useless, the most you will see them do is chase the mail carrier.

Drat! Maybe somebody will make a mod then. I would love to be able to give some of my sims guard dogs.

Yeah. Would have been cool If they were capable of chasing away approaching burglars or even repo man.

Pets do get hostile (bark at, hiss at, chase, etc.) the Unsavory Charlatan, but it turns out that those are the pets' ONLY options to interact with him. If you use the cheats to make pets controllable and click on the Charlatan, you don't get any other options. It's funny to watch a dog chase him all over the lot though.

I'm the same, but I'll try to train dogs to stay off the furniture too. Cats I'm not so picky about - RL cats will sit wherever, and training them is about as easy as herding them! If I can encourage pets to be playful rather than hostile, I will, but it's not something I tend to bother about.
Regarding the anti-stink, it's more to discourage the hole-digging than anything else; it's far easier to just pick up dropped rubbish than it is to fill in the holes and it can be amusing to watch a sim attempt to bath a reluctant dog.