Wiktionary
that does it
interj. 1 (context idiomatic English) (non-gloss definition: Used to express annoyance or frustration or announce that one has reached the limit of one's patience or temper) 2 (context idiomatic English) (non-gloss definition: Used to announce or assert completion of a task).
Usage examples of "that does it".
But you know how it is, it's not just he way they look that does it.