I’ve been thinking about this very thing for a while now. Typically, I don’t like grid patterns with a square foundation that don’t interact in some way from one cell to another. There should be some kind of angles or overlap from one cell to the next. Even better is when you can’t easily spot the borders from one cell to the next.

Owen Jones had it figured out 100 years ago.

“In surface decoration, any arrangement of forms, as at A, consisting of only straight lines, is monotonous, and affords but imperfect pleasure; but introduce lines which tend to carry the eye toward the angles, as at B, and you have at once an increased pleasure. Then add lines giving a circular tendency, as at C, and you have now complete harmony. In this case the square is the leading form or tonic; the angular and curved are subordinate.

We may produce the same result in adopting an angular composition, as at D: add the lines as at E, and we at once correct the tendency to follow only the angular direction of the inclined lines; but unite these by circles, as at F, and we have still more perfect harmony, i.e. repose, for the eye has now no longer any want that could be supplied.”

– Owen Jones, The Grammar of Ornament–1910