A Nana is a very important person in you're life. You need them to help you with hard times and situations where you can't do something alone. They are important to you because you love them and care for them all the time.
Example: You are the best Nana ever!
You're Dad is the most reliable and trustworthy man in the world. You know you can count on him in any situation. If you have a problem, you're Dad will be the one to help you.