They are some of the darker moments of parenthood and we have, or will, all have them. We probably even remember some of the ones our parents had with us. When the normally reassuring voice rises to a yell, the soft and sweet face contorts into a scary mask, when the comforting body stiffens to a launch position following a screamed threat, a raised hand, an incriminating finger, or an icy promise of abandonment. Moments like these are the fruits of exhaustion, tripping of a "trigger wire" from our past, the depletion of patience, the rubbing on a particularly raw nerve, and/or the sense that we are now both beyond the natural limits of human endurance—physically and emotionally.
