It sounds obvious, but even veteran politicians sometimes forget. Senator Jim Watson (right, 1862-1948) was in office for six terms. But when he said, “You can vote for me or go to hell," Watson lost the next election.
Hearing of Watson's gaffe, Calvin Coolidge quipped, “He gave them a difficult alternative.” (Capping irony: If you visit Watson's official Senate page, it has the heading: James E. Watson: "Impossible Not to Like.")
Crockett left town
*My sources are here.