For ours it's the Thing on Top of Another Thing. Like if there's a shirt on the bed, it's better to lie on the shirt than anywhere else on the bed; if there's a magazine on the table, it's better to sit on top of the magazine, etc.
This would all be better than what I really have to come up with.
I noticed this with my cat and I wonder if this is like Ritz crackers* where there's a maximum good on topness. Like is a magazine on a newspaper on a shirt on the bed better than just a shirt on the bed, or is that too many layers? These are the questions that keep me up at night.
*"'Everything,' I am told, 'tastes better when it's sitting on a Ritz.' No exception is made for other Ritzes, so from this statement we can infer that any given stack of Ritz crackers tastes better than any smaller stack of Ritz crackers, and thus the tastiest stack of Ritz crackers is the tallest one that you can fit in your mouth." - Lore