I came across this phrase that I don't understand. What does it mean?
frustrates the life out of me
I want to know how to use it too.
"- the life out of me", usually "scared the life out of me", is an idiom. It loosely means "until I had no energy left". If something frustrates the life out of me, I am exhausted from being so frustrated and feel like I can't do anything else.
It would be more common to say "... frustrates the hell out of me" or "... scares the life out of me". I'd avoid overusing this sort of idiom.
Literally, it means to frustrate to the point of death. It's the same basic pattern as "to crush the life out of", as a constrictor snake will crush the life out of its prey before it begins to feed.
If anything ever literally frustrated the life out of you, you'd no longer be in a position to tell us. However, something can frustrate you beyond what you are willing or able to tolerate. In such a case, this phrasing makes perfect sense.