I asked my Dad one day what he wished he would have known at my age. His response was a good one; one that books- and the Good Book- having been telling us in one form or another for years: "Don't look for what isn't there." Meaning this, be thankful for what you have. Look at how God has blessed you. Be satisfied with that... and keep your heart focused on the things that are important to God.
Thanks, Dad! It was good enough to pass on to others.