Fighting vainly to keep conscious during mediation after Mass. In fairness, the conscious/unconscious ratio at the original Gethsemane gave long odds as well.
It occurs to me that I've spent a considerable amount of time in recent years functioning at my absolute physical and mental limit, given the circumstances. I have my doubts as to whether this is an unalloyed good. As bad as it is to be comfortable, difficulty, especially when extreme and extended in time, can transform the action.