I’d have to say a mix of physics, timing, and fluid natural motion. With cars and stuff like that im always thinking about what little motions can manipulate the car, like IRL if you where sitting in your car and you.. idk slammed your head into the wheel or sum, it would move the car a lil, depending on the cars size, weight, what gear the car is in ect ect. And I have to also watch out for inconsistencies in the suspension motion, like if I am animating with a 2015 camry sport, I will animate the suspension a little stiffer then that of say a 67 chevy impala, because suspension of old cars (60s chevy sedans, caddys, pontiac sedans ect) all had cloudy, soft pillow like suspension because that was what was luxury back then. Soft and comfortable, nowadays however, automobile suspension even in modern luxury cars (BMWs, mercs, caddys ect ect) suspension is stiff for “performance” and “handling” so I have to account for that in the anims I make.

Also load is a key factor, take a 90s regular cab 1500 pickup, any pickup rally, ford, dodge, chevy, they all have a slight racke to the front (which looks mean lol), this is so that when you load the bed, the truck is still even. In my anims, I try to pay attention to this. If a trucks bed is unloaded, it’ll be more stiff and bouncy then that of a truck with shit in the back. Just basic physics.

For characters it’s different, I learn the way a character acts from a show or movie or something and try to replicate that in my anim.

Take dean winchester, he has a distinctive thing he does with his Eyebrows, where when he’s angry, they look like a zigzag, but when he’s not angry, they are still kinda zigzagy but way less. Same with his mouth, eyes and body movement (I do this for every character I animate)

Idk though, it all feels weird in a way

actually starting