“Just like the children [in the marshmallow test], we’ve been asked to wait out a temptation in exchange for greater rewards in this life or the next (and we tend to cheat in fairly similar ways). But the experiment also exposes some reasons that this understanding of God’s rules may wind up leaving a bitter taste in our mouths. In the experiment, the children are exposed to an arbitrary test – there is no reason that eating a marshmallow now should preclude a treat later, except that the experimenters deem it so. Without a good reason for the adults’ demands, the children can play along, but they have no reason to trust or love – they have every reason to look for a loophole or a trick.
A number of recommended Lenten sacrifices (sugar, coffee, etc.) seem to be suggested simply because they are difficult. As in the marshmallow test, the sacrifice is arbitrary, not a positive reshaping of our lives that we’d want to continue after Lent. These sacrifices are valuable only in that they are hard, a chance to do something costly for God.
It can be nice do something flamboyantly generous for a loved one, and Christ praised this impulse in the woman with the alabaster jar, but exhausting ourselves in arbitrary ways has the potential to remind us less of the woman with the costly oil, and more with all the other painful, pointless-feeling sacrifices we practice on a day to day basis.”