I'm about as nuts a Witchy is. We share our lives with four SVs, F5 Diablo, F4 Mickey blue eyes, F3 Jarvis, and f2 Baby Rey aka floofy.
Baby Rey is the lightest of our bunch, at 10 lbs, but she is as tall as 15 lb F5 D, and taller than 12lb F4 Mickey.
Jarvis is our big boy, he is 20 lbs. A photo of Jarvis is below. 20lbs of cat is a LOT of cat. 20lbs of fit, muscular, strong cat is a heck of a lot of cat. You might think you want big, but it isn't easy to manage a big kitty when he is upset and doesn't want to do something or doesn't like someone in his space. Deb mentioned that about Atticus above. I'm echoing it.
When Jarvis doesn't want to do something, it doesn't happen.
As others have said, SVs are SVs. The explanation about the difference in intensity is pretty spot on, as is the explanation regarding the meaning of the word "no".
Of our bunch, F2 Baby Rey is pretty easygoing. She is persistent about three things: play, food, and snuggling. If she wants to eat, she is going to to harass you until you feed her. Even if she has just eaten. If she wants to play, she will bring us a toy. If she wants to snuggle, she is going to snuggle with you. If you aren't sitting or lying down, she is going to harass you until you are. If all else fails, she will lay down on or at your feet, and then whine at you if you move.
F3 Jarvis is extremely stubborn. He has a whole host of behaviors he engages in when he wants something. He doesn't stop until he gets what he wants. He is MUCH more stubborn than either of the humans are. He doesn't follow rules well. We have made great progress, but he is like a 2 year old. He constantly needs positive reinforcement. He never stops pushing the boundaries. Jarvis is also up there regarding smarts. He can open doors, drawers, and cabinets. We had to get a new fridge because he was raiding our old one.
F4 Mickey is between the two of them. He is very persistent when he wants something, but his three wants are the same as Rey's. He is also the easiest of the bunch to satisfy, but for the snuggling. I don't want him to sleep on top of my legs. He wants to sleep on top of my legs. Therefore, he sleeps on top of my legs, and if I move him, he just moves back.
F5 Diablo is our smartest kitty. He is *mostly* well behaved. He walks on a leash and a harness, he knows and mostly listens to come, sit, down, up, drop it, and leave it. He is great with adults and with children. He likes EVERYONE.
Diablo came home first, followed by Jarvis, then Mickey, then Rey. I love all four of them very much, but they are all nuts in their own way. I would agree that the lower generations are *mostly* less stubborn and intense, but there are outliers, like Deb's F6 boy.
