When I was a youth I used to take all kinds of pledges, and do my best to keep them, but I never could, because I didn’t strike at the root of the habit—the desire; I generally broke down within the month. Once I tried limiting a habit. That worked tolerably well for a while. I pledged myself to smoke but one cigar a day. I kept the cigar waiting until bedtime, then I had a luxurious time with it. But desire persecuted me every day and all day long; so, within the week I found myself hunting for larger cigars than I had been used to smoke; then larger ones still, and still larger ones. Within the fortnight I was getting cigars made for me—on a yet larger pattern. They still grew and grew in size. Within the month my cigar had grown to such proportions that I could have used it as a crutch. It now seemed to me that a one-cigar limit was no real protection to a person, so I knocked my pledge on the head and resumed my liberty.

—Mark Twain