The neck joint is kind of interesting. I never thought too much about it being a joint. But it does provide a pretty wide range of movement in a half circle axis. Wouldn't it be something if our necks joint was designed like an owl. Then we could turn around only our heads and see what's going on.
Some of our other joints just move up and down, like fingers and toes. Others, like the thumb, ankles, and wrists can go up and down and side to side.
I have over-extended joints, or what some call double jointed joints. They move farther than they are supposed to, so I have had quite a few chronic injuries to my various joints. Not a fun situation. But I can still bend down from the hips and touch the floor with flat hands!