Haha I have a cute little lap dog that curls up with me on the sofa but also refuses to learn! He is a dachshund and very intelligent, too intelligent and I think he loves to defy me.
He is not allowed upstairs, he couldn't actually climb them but he loves nothing better than to sneak into the living room if someone leaves the door open. You go in and he actually looks you in the eye before running around like Road Runner. I know it's not good, but we just Benny hill it now.
He wants to be on your lap, can't get close enough to you. Watches you eat.
Toilet training has been interesting, we are getting there but will he do a poo and a wee in one visit? Will he buggery, it's like he knows that's a two treat job and if he does it in one, he misses a treat.
I reward lots of good behaviour and ignore the bad. Like others, managing him physically is key but obviously him being so small helps. Chairs all have to be shoved in and we have to lift up the cushions on the sofa so he doesn't jump on them. I'm not offended by him being on the furniture - but him being the breed he is means a delicate back and jumping up and down isn't recommend.
He will refuse to go out if it's raining, for toilet let alone a walk. I pick my battles. Literally pick him up and wait for him to finish his business for the toilet, and we don't walk in the rain which suits me!
Luckily the fact that he's cuddly makes up for the fact that he is a massive dickhead.