They look great to me, no need to be embarrassed! These remind me of the sketches I used to do in fine arts to practice forms and shading. It was the same idea— 20 seconds to 1 minute each. It is difficult but really helps me develop forms very quickly without over thinking it.
I really enjoy this thread, and I’ll keep following along. Since you have a lot of cool coffee-inspired ideas, maybe you could try your take on a pour over system?