Done as part of a practice session with poses of 60 seconds in length.
My current goal is: Better understand human anatomy, so I can render imagined poses
Tried to focus on face structure
I really love the laughing faces; they look pretty energetic! However, it seems like you're adding detail at the expense of the underlying shape of the head, and it's making some of the neutral faces look really uncanny.
When I practice heads, I use the shorter drawing sessions to focus on the general form of the skull, jaw, and neck, with some cross contour lines and maybe a nose and some eyebrows. I only start to add in facial features and details in longer drawings, once I've had time to nail down the general head shape.
Maybe you could try doing something like that and see if it helps.
Retrodictionary
When I practice heads, I use the shorter drawing sessions to focus on the general form of the skull, jaw, and neck, with some cross contour lines and maybe a nose and some eyebrows. I only start to add in facial features and details in longer drawings, once I've had time to nail down the general head shape.
Maybe you could try doing something like that and see if it helps.
J Canard