When you ask this question, we should try to understand who can answer it best. Parents or children? As for parents, they usually work hard to build better lives/better living conditions so their children can live and be educated at a high level. But as for children, when you ask them what would make them happy, they definitely say that love from their parents is the most precious gift. They'd like to share their happiness with their parents, and they need comfort from their parents when they feel sad. The relationship between parents and their children can't be measured by money or materials [perhaps "material possessions"]. The best way to maintain the parent-child relationship is to have them make friends with each other. No matter which of them faces difficulties, the first people who come to their mind will be their parents or children. We need to realize the true meaning of family again, just from how to get along with our children.