An attitude of gratitude
Counter complaining! Counter complaints by encouraging children to appreciate the good in their lives. Much of our happiness is determined by the social comparisons we make. When we compare ourselves to people we think of as better than us, we feel deprived. When we compare ourselves to people who are less fortunate than us, we feel grateful. When your child focuses on those who they feel have it better than them, remind them of those who are less fortunate. Recognizing that there are those less fortunate than them helps build empathy, gratitude and appreciation.
(U.S. Dept. of Defense/Wikimedia)