Silly Mimi

Why do cats do the silly things that they do? I was at my workbench the other day and just kind of stopped to watch Mimi squeeze herself under my little bookshelf which only has a few inches of space under it. She got under there, laid there for a little while, and then was done and crawled back out. Good thing she is tiny, I can just picture one of the bigger cats doing this, and then walking around with a bookshelf on their back because they got stuck.