When we are attacked, our survival instinct tells us to defend ourselves either through withdrawal or counter-attack.
Repteated withdrawal, though, tends to decrease our self-confidence and lead to a sense of powerlessness and depression.
Or it may eventually isolate them from their feelings, with a resulting loss of major part of their natural intelligence. Most of them are so insidious that we don't even know what is happening.
We know that something doesn't feel good, but we sometimes can't put our finger on it.
On the other hand, going on the offensive often escalates the conflict or puts us in the position of trying to change another person.
But trying to dress an emotional wound, with logic tends to either confuse, sadden or infuriate a person.
Examples of such relationships are parent/child, teacher/child, "spiritual" leader/follower, boss/employee, spouse A/spouse B.
Such a sad scenario appears to be even more likely when the person being invalidated is highly sensitive, intelligent and has previously suffered self-esteem damage.
In abusive homes, they may have been severely punished for expressing certain thoughts and feelings.
When your awareness rises, you'll begin to notice such comments on a regular basis. We wonder if there is something wrong with us for feeling how we do.