Criticism can be helpful, even inspiring, but never — when it descends into chronic whine or becomes a way of life. If there is someone in your life that you feel especially free (or, worse, 'obliged') to criticize; try this:

Every day for an entire month, find at least one specific thing that you will speak about positively and directly to that person.
• Explicitly encourage, express gratitude or praise them.
• Take an interest in their interests. You don't need to take on their interests or share them; but offer your curiosity and willingness, to listen as a mark of respect for who they are and what concerns them.
• Keep finding fresh, new things to comment upon positively — as well as what you praised yesterday or the day before.
• If you hear yourself begin to criticize, STOP. Leave the room.
• Only by behaving less critically will your habits of criticism begin to change.

If you feel silly or self-conscious, regard this as a tiny, private act of reparation.
You are doing this primarily to express your respect and affection for that other person and, only incidentally, to grow in self-respect.
You are not doing it for praise! And you won't stop doing it if you don't get enough praise.
Enjoy the benefits as the people around you respond, relax, rejoice.

Stephanie Dowrick in Choosing Happiness: Life & Soul Essentials