One who knows what is good for them gives up being judgmental. This does not mean to abandon pragmatism or discrimination (as in "this is appropriate, this is not"). It means abstaining from applying value judgments to others or to anything that the universe, in the supreme abundance of its infinite diversity, provides. When you judge others, it is most fundamentally an affirmation of the subconscious misnomer of "I" as distinct from "an other". Truly, all are One. Suffering stems from our not recognizing this.
The lack of recognition is reinforced as we act according to the lie. Even if we can't presently perceive this fundamental unity for ourselves, our lives will be benefited if we can apply the principle of ahimsa (non-harming) to our lives and interactions with others. This makes sense as harming others (in thought, word, or deed) is to harm oneself. If you prick your finger, it hurts you. Even if the fingers holding the pin regard themselves as separate from their victim, they're not; its pain is their pain. Any time you point a finger, you can count on having that finger pointing back at you. Conversely, when our interactions with others are characterized by selfless giving, without conditions or expectations of some sort of payout, one sows the seeds of happiness.
Carrying the concept of non-judgment out further still, we should strive to apply it to everything that arises before oneself: the eternal "I AM". This is also often framed in terms like "surrender to the Divine" and "gratitude". The more we cultivate this attitude - the attitude that whatever God provides in any given moment is enough - the more our lives flow in harmony with the universe. We can swim against the current - wishing for something that didn't arrive, wanting some future payout, etc. - but this is exhausting. It generates suffering.
This universe is all just a dream. Its contents can't harm you, and whatever the dreamer provides is neither deficient, nor is it too much. There is room here for whatever happens to happen. Still your own essential nature is ever unaffected. It can only ever seem to hurt you and, even then, only because you have given your permission by believing the lie. The unfolding of the universe, as a general rule, carries on as it will, regardless of our opinions of how it does so. Keeping an eye toward the Real allows one to increase their acceptance of what is, to increase their gratitude, to drop their judgments. In the process, you lose 'you' and find that there was only ever the Divine in the first place. This is the Supreme Bliss. Know This and be happy. OM Namo Narayana!