A square towel for bikers is one of my “helmet stuffers” – gloves, head sweat, and bandana. One step in attiring for a ride is to tie a square towel loosely around my wrist, using two adjacent corners and a square knot, then tucking the rest into that wrist loop.
My square towel is always “at hand” for deployment with a tug of the teeth. Or use on freezing descents, for farm machine dust clouds, as bandage ties (torn in half), for leverage on stubborn skewer handles, as hot pan holders… the list goes on.