"Never apologize and never explain-it's a sign of weakness."
John Wayne
As jarring as this will sound to many of you, it is a philosophy practiced by many managers. Too many in my opinion.
Start with the premise that apologizing or explaining is a "sign of weakness." We are all, at various times, "weak", if we define "weak" as deficient in certain ways.
Who isn't? But being weak does not mean we can't take corrective action to become strong.