Criticism Speaks (but to whom?)

When we judge or criticize another person, it says nothing about that person; it merely says something about our own need to be critical. - Unknown

To Reap, You Must Plant

Don't judge each day by the harvest you reap,
but by the seeds that you plant.
Robert Louis Stevenson

A Book's Cover

We don't judge a book by its cover but the contents to be read inside. So I ask, why are we quick to judge others by just a glance?