I'm skeptical of the grocery store claim. Do you have anything to support the claim that one layout is more common than the other (and that would further suggest it's for this reason)?

If I think of all the grocery stores I've been in, I can think of many examples of clockwise layouts. Much more so than counter-clockwise, but that's likely because of my personal brand preferences. The factors in the layout seem to be dominated by:

1. The position of the entrance (if the store is part of a mall, the entrance is often predetermined, and only one layout will be feasible).

2. The brand of the store. Thinking of Canada (and in my experience) Loblaws brand tend to be clockwise, and Sobey's counter-clockwise.