The correct question: "Is your best worth the cost of dealing with your worst?"
The personality types that used the [can't handle me at my worst] line, even if they don't say it that way anymore, are all types whose bests aren't worth the hassle. The very fact they have to say something like the line is proof.
A fortiori: humans are excessively loss-averse. Humans will put up with a tremendous amount of bad to keep a small amount of good. If the bad is overpowering the good already, it's way way beyond anything a reasonable being would put up with.
In short, "What best? You're all worst all the time."