is there a general rule or tendency about temperaments of big dogs and small dogs? like which are usually more friendly and affectionate, which are easier to live with? from my understanding small dogs are very often yappy and big dogs are more clam. what do you think?
I think it also depends on the individual dog, but yes, big and small dogs do act differently.

Lots of small dogs have a kind of Napoleon complex. They think they're six feet tall and they have a personality that's bigger than they are. They can get yappy! My Maltese mixes bark at every noise and when they play, much more than the big dogs do.

My golden retriever is very loving and hardly ever barks. She loves to curl into a blanket and sleep, and she's very gentle while playing with the rough little dogs. My lab is insane, she's hyper and awkward and barks randomly to get your attention. She's more like the little dogs with energy.

The little dogs also resent being lifted up and bothered when they're sleeping, whereas the big ones can be rolled on, layed on, and poked and they don't care.

They're all very very affectionate and sweet. I'd personally pick a big dog over a small dog, because big dogs are easier to hug Emotion: smile It's just their personalities that are different. But yes, there are differences between small and big dogs.
They are stereotypically this way because most (not all) the people who get these smaller breeds think it is ok to let small dogs get away with everything and treat them like babies and not the dogs they are. For some strange reason it seems to be exceptable that small dogs are this way but if my husky acted the same way as the majority of chihuahuas/yorkies/jacks etc he would be classed as a 'dangerous dog'. It definetly depends on how they are brought up although some breeds are more susceptible of having certain traits so need a bit more work to keep them at bay.