I sit close to the bottom one. Apparently, a coping mechanism of undiagnosed ADHD, now diagnosed but hard to break the habit.

So in the office I sit kind of like the bottom image but my feet are in the seat. Maybe one sole down and the other foot I’m sat on.

At home my lower back is on the seat and my legs are on my bed.

Isn’t lumbar support just a bit of marketing that Herman Miller made up in the 90s and that those kneeling chairs are actually the best ways to sit for long periods of time?

Weird. Here™ (swiss), we learned that always looking down (phone) is bad for posture.

Btw, screen top should be at least eye level.

Old people (I’m not even old yet) who used to sit like the below picture and have incapacitating back pain when they sit wrong now.

From what I understood it’s mostly about changing positions all the time. Any static position will cause discomfort if held for too long.