a ragged colt may make a good horse

a ragged colt may make a good horse

Someone's or something's current behavior, condition, or situation, especially that which is bad, does not dictate their future outcome. I wouldn't worry too much about your son's interest in partying—a ragged colt may make a good horse, after all. The rough cut of the film left us a bit worried, but the editor assured us that a ragged colt may make a good horse.
See also: colt, good, horse, make, may, ragged