Meatless Fridays for Catholics in England and Wales
While there is a standing obligation to perform some form of penetential recognition of the day, I know that I often do not do so--more often than not. Not because I'm unwilling but because the law itself is too nebulous to be of help. When it is expected of all (Ash Wednesday, Good Friday, and the Fridays of Lent) it is relatively easy to observe.
A moment out to remember what we are about as a people is salutary. Perhaps the obligation should be more other-focused--but that is hard to do without serious interference in daily life. For example an obligation to serve at a food station for the homeless, or to take a home-bound neighbor to the store, a doctor's appointment, or other needed or desired destination. These would be the penance not of "sack-cloth and ashes" but of "liberating the poor, the lonely, those imprisoned unjustly" etc.
But this sort of penance would suffer from the present Friday obligation--nebulosity. So some reminder that we are eternally in debt and that debt may only be paid to others is a good and necessary thing.