Why do we buy toys???

Last week, Grant started pushing his little convertible pushing/riding toy that we bought for him a while back. He can't steer yet, but he loves to push that little thing all over the place. But.....yesterday we went shopping and bought a package of toilet paper, and I left it laying on the kitchen floor. Last night, while Grant was pushing his car, he pushed himself right over to the toilet paper and started pushing that instead! It was very cute....but since it has no wheels, it was a lot harder for him! He had to stop after a while and was breathing heavily! Things like that always make me wonder why we even need to buy toys for our kids....a lot of times they're much happier (or just as content) exploring and playing with everyday objects around the house!