^Agree, although I hardly ever hear it used.
Another extremely dumb one that came to mind: "The exception proves the rule."
Especially when they started out arguing that something has no exceptions, then you name one or two and then they counter with this.
Oh and inb4 Frown starts teaching us about the original and actually sensible meaning of the phrase, here's a link:
https://en.wikipedia.org/wiki/Except...roves_the_rule