" While parents like Cyndi Paul find it heartbreaking to start imposing discipline, children react well when reprimands are delivered briefly, calmly, and consistently, according to Susan O’Leary, a psychologist who has spent long hours observing toddlers and parents. When parents are inconsistent, when they let an infraction slide, they sometimes try to compensate with an extra-strict punishment for the next one. This requires less self-control on the parents’ part: They can be nice when they feel like it, and then punish severely if they’re feeling angry or the misbehavior is egregious. But imagine how this looks from the child’s point of view. Some days you make a smart remark and the grown-ups all laugh. Other days a similar remark brings a smack or the loss of treasured privileges. Seemingly tiny or even random differences in your own behavior or in the situation seem to spell the difference between no punishment at all and a highly upsetting one. Besides resenting the unfairness, you learn that the most important thing is not how you behave but whether or not you get caught, and whether your parents are in the mood to punish. You might learn, for instance, that table manners can be dispensed with at restaurants, because the grown-ups are too embarrassed to discipline you in public. “Parents find it hard to administer discipline in public because they feel judged,” Carroll says. “They’re afraid people will think they’re a bad mother. But you have to get that out of your head. I’ve had people stare at me when I take a child out of a restaurant for being rude, but you can’t worry about that. You have to do what’s right for the child, and it really is all about being consistent. They have to grow up knowing what’s appropriate and inappropriate behavior. "

― Roy F. Baumeister , Willpower: Rediscovering the Greatest Human Strength