Terminal

No pictures, no buttons: you type a line, press return, and text comes back.

You'll meet it less than you fear, most of this can be done without ever opening one, but you will meet it, usually to start the app or find out why it didn't.

Two things throw people. It's not dangerous by itself; it does what it's told and nothing else. And it offers no encouragement: a command that worked often says nothing at all. Silence is success.