Knowledge, skills, and attitudes children pick up from grandparents tend to stick with them through life more than those picked up from other sources. They don't feel the pressure they felt as a parent. There's a saying that a mother truly becomes a grandmother the day she stops noticing all the terrible things her children do because she's so enchanted with all the wonderful things her grandchildren do. As a grandparent, you get all the benefits and joys of parenthood without many of the drawbacks. Maybe you weren't able to spend as much time with your own children as you would have liked, or made some mistakes you've now learned from.
Grandchildren are a fresh start.
Active, involved grandparents consistently report much less depression and higher degrees of life satisfaction. They tend to be happier with their present life and more hopeful for the future. Grandparents and grandchildren fulfill the role of student and teacher for each other, and it's not always the older person who does the teaching. Grandchildren also help you see the world anew again, through a child's eyes. Grandparents have an opportunity to leave a powerful legacy, to make a difference, to send a message into the future through their grandchildren.