Because God is good.

Because thy loving kindness is better than life, my lips shall praise thee. Thus will I bless thee while I live: I will lift up my hands in thy name.

Psalms 63:3-4 

It was because of all the good and protect that David had received from God that he wrote this Psalm. God had provide for him everything he needed and more. And in David's heart he promise to lift up his hands unto the Lord all the rest of his life. 

How often has the Lord blessed you when you didn't think you deserved it. For me that is all the time. How often has God protected you from harm and shown you that he is with you. Again I can attest to many of time He has done that for me and my family. God is so good to all of his children. The very breath in your body right now is a sign of his loving kindness to us. And because of those things that is why David write that God is better than life, because he gave you that life you have and he keeps giving you that life.  Nothing in this world could give you life without God, but with God you get more than just life. If you are and child of God you get life everlasting. And if you are not saved, then it's time that you come to know how great the Father really is. Until the time comes when you do come to Him, I'll lift my hands to Him and I will write, preach,sing and praise him always.