As director of Duke's Behavioral Medicine Research Center, Williams said he recommends that people ask themselves four questions before deciding to react to a potentially volatile situation.
Is this situation worth continued attention?
Is my anger appropriate?
Is there a way to modify the situation?
Is it worth it to take action?
Williams said he often uses the example of a screaming child in exercises to show patients that it really isn't a reason to get angry, unless the person is trapped with the child in a theater or airplane.
"If you really think about it, that's what 2-year-olds do," he said.
Stephens could have chosen to just walk away from the child in Wal-Mart, he said, or politely asked the mother to please quiet her child.
"People like this guy could benefit from learning there are more effective ways than what he did to change their and their kids' behavior," he said.
Psychologist Alan Kazdin, director of the Yale Parenting Center and Child Conduct Clinic, said the answer to quelling displays of unruly behavior is easier than most parents believe. "Of course," he said, "hitting is not" the appropriate response.
Most parents wait for the tantrum to happen and then get angry and threaten to leave the store, put the child in a time out or take away a privilege later.
"This is where most parents normally go wrong," he said.
The best way to avoid a tantrum in the first place, he said, is to get in the habit of taking a child to the store and immediately praising them for their good behavior, topped off with a quick hug or pat on the head.
In doing this, he said, "the chance of a tantrum is wildly reduced."
But in the heat of the moment with the child is screaming and hitting, the best thing to do is just calm the child by using a soothing, but matter-of-fact tone to tell them the behavior isn't acceptable and that the outing will be over soon.
"Don't be angry, don't be nasty," he said. "That'll make it worse."
Another fast way to make a bad situation worse? Trying to interfere when the child isn't yours.
While some may recommend aggravated bystanders calmly ask a struggling parent to please quiet their child, doing so, Kazdin said, will only turn a frustrated parent into a defensive one.
"There's no way you can do that," he said, "without offending the parent."