First, parents may react as though something is a problem when it is not. A father, for example, may worry about his teenage son's moodiness and detachment. Another parent may worry that her preschooler is too shy. Only if the child is miserable. Moodiness is a problem if it becomes depression or aggression.
Shyness is a problem if accompanied by painful isolation.
You avoid the something is a problem when it is not mistake by understanding what is reasonable and unreasonable for children depending their age and temperament. In this example, you might decide that biting cannot be overlooked. Violence of any kind is learned, not inborn, and a problem that has to be taken seriously. The second type of mistake reverses the first. Parents may react as though something is not a problem when it is.