Cats enjoy many things in life, out of all of these, superiority over all other creatures is the most treasured. Though WE know we're superior, some creatures (humans) don't acknowledge it.
So, a good way to prove our superiority to them is to get up high, in the tops of bookshelves, closet shelves, really any kind of shelves. Then we can look down on them, on everything, as it should be.
-Clark the superior Cat