"Life, as I've often remarked, is an elevator." The speaker doesn't so much mean that life has its ups and downs but rather that one gets smacked into reverse repeatedly ("biff!" and "boomp!"). His companion replies that most well-conducted elevators have somebody inside to keep them "from biffing and boomping up and down to no purpose." The answer: "There ain't in life. Or if there is, he's drunk most of the time. Or else crazy." (From Pearson's, 1909.)