Imagine a situation where you were at the playground on the seesaw with your older brother. It works well at first. Then winter comes. The next spring you hop on the seesaw again, but it doesn’t work anymore. Your brother grew faster, and now the seesaw is out of balance. He gets on, you fly up on your side, and you’re stuck with your legs dangling in the air, suspended until he lets you down. Your seesaw is out of balance. You need to rebalance to make it work the right way again.