Now this is interesting:

Self-Regulation and Depletion of Limited Resources:  Dose self-control resemble a muscle?
Mark Muraven & Roy Baumeister, Psychological Bulletin (2000) No. 2, 247-259

Abstract: The authors review evidence that self-control may consume a limited resource.  Exerting self-control may consume self-control strength, reducing the amount of strength available for subsequent self-control efforts.  Coping with stress, regulating negative affect, and resisting temptations require self-control, and after such self-control efforts, subsequent attempts at self-control are more likely to fail.  Continuous self-control efforts, such as vigilance, also degrade over time.  These decrements in self-control are probably not due to negative moods or learned helplessness produced by the initial self-control attempt.  These decrements appear to be specific to behaviors that involve self-control: behaviors that do not require self-control neither consume nor require self-control strength.  It is concluded that the executive component of the self- in particular, inhibition – relies on a limited, consumable resource.

So… some situations extract a cost in self-control resources.  If that cost is high, the next event requiring self-control can’t be “purchased.”  More important, not being aware of the cost, I may not gauge accurately my ability to be skillful in engaging with the next event.  Others authors/researchers have talked about mindfulness as a muscle that supports awareness in the service of self-control (not getting hung up here on the self-non-self issue).  In essence, it’s about how seamlessly we can re-set from one exertion to the next and, I think, only practice will strengthen that particular muscle and replenish that well.

Time to log more hours on the cushion.

Thank you for practicing,

Genju