Which is the garden tool(s) that you can't live without?

We can't work in our gardens without tools that make our work easy. It's like having an extension of our hands for the purposes of accomplishing tasks that otherwise would be difficult.

I'd like to hear from gardeners about the tool(s) that you must have in your home. I'm talking about that tool you can't give to anyone who borrows it or let anyone use it because you don't want to lose it.