It’s a bit off-side, but another sad part of this quote is that it actually sounds reasonable in the original context:
I’m selfish, impatient and a little insecure. I make mistakes, I am out of control and at times hard to handle. But if you can’t handle me at my worst, then you sure as hell don’t deserve me at my best.
Marilyn Monroe went out of her way to list what she considered her “worst”, that is in direct contradiction with the “best” (that everyone could see) from her public persona. She’s saying “Here’s my worst; you know my best. If you don’t accept me for who I am, you don’t deserve that sex symbol that I built”.
It’s a fair cry from how people often use this quote, where they justify making your life a living Hell under the promise of some “best” that you’re never going to see.