If you believe the Bible, the Bible is A Bowdler’s version of “Good God!” They have been titled “Good Lord! ‘ “”, which is, in turn, a shortening of the liturgical response “Good Lord, deliver us”. In this case, it’s a response to a clear and present bit of unpleasantness, often a mechanical device that won’t co-operate or a vexatious person.

Could the little Peanuts characters of Charles Schulz had no bad word for “Good Lord”??

It is an expression of exasperation, informal.

I have good grief to express. It’s an expression of irritation. Is it so good? Is it an informal expression? What do you say if you wear this expression?