Okay, we're going to level with you. You have to back up your data, and we're going to tell you some of the reasons why.
First of all, you already know why. It's your data, and you don't want to lose it. Whether it's just a few files or your entire business, it's worth taking the time to make sure it's safe.
Second, you need to admit the fact that all computers are living on borrowed time and eventually will fail. Even the best hard drives in the world are temporary, and backing up files is your protection for when the inevitable happens.