The phrase "I can take a hint," when said seriously, contains its own denial. It reveals that the speaker has not been very adept at recognizing the hints already given, nor very graceful about not making a scene once he has recognized them. Its very utterance has the effect of punishing the hint-giver by making her hint fail as a hint. The truly successful hint works by gaining its end with no extra awkwardness added to the social encounter. The good hint should be barely perceived by the person toward whom it is directed. We could even say that it should not really become a part of his active consciousness. It should simply trigger a sense that it's time to go or that the line he is pursuing needs to be terminated. The good hint achieves the invisibility of the natural.
Miller, William I. "'I Can Take a Hint': Social Ineptitude, Embarrassment, and the King of Comedy." Mich. Q. Rev. 33, no. 2 (1994): 322-44.