There’s something aesthetically pleasing about curves. I wonder if it has something to do with sex: it reminds us of the female form. If so, then it’s a very (straight) male-centred aesthetic standard.
Maybe the appeal of curves is something more elemental. Elemental? you ask. What could be more elemental than sex? How about our need for order? Curves are inherently balanced: they go one way, then they go the other way. A good curve eases our anxieties.
Curved paths in a cemetery? Maybe there’s something pastoral about the juxtaposition. The comfort of the curve answers the angst of the grave: