Huh. Surprising how many people posting have stall showers. The only time I've ever lived in a place with a shower not situated over a bathtub, it was in a barracks, in the Army.
So yeah, shower to bath and vice-versa is all the same to me... though I usually lay down, as opposed to sitting or squatting.
...also... yes, I waste a lot of water, but I'm not connected to city water. I have a tapped spring on my property that flows 24/7 into a stream and provides far more than I could ever use. It's also only one of three on my property.
Additionally, my gray water output goes into a gravel filter, so wasting might not be the right word for my water use.