The following is taken from Improve: Now is the Acceptable Time! distributed by the Archconfraternity of Christian Mothers.
That Added Measure:
A thoughtful person goes the extra mile and does more than he has to do. You are told to polish the kitchen floor and end up by doing the basement stairs for good measure. Mother asks you to go upstairs for a pair of scissors, and you pick up the basket of clothes at the bottom of the steps and take it with you. Going the extra mile is like the shine on your shoes, the icing on a cake, the shock absorber on a car, or the power on your nose. It's not necessary but it does help.