From someone who knows how to use it. This should be you, but usually involves some training.

You.

From me and the people I choose.

From Microsoft, Apple, Adobe, etc.

Oh, I'm sorry, Sir, go ahead, I didn't realize you were root.

From Dave.

I'm sorry, Dave. I'm afraid I can't do that.

What's that? Chicken?

ME!

Proprietary software means, fundamentally, that you don't control what it does; you can't study the source code, or change it.