It's easy to be optimistic yet not achieve our success potential. God can help us become far better than we can become by ourselves; thus left to ourselves, we might see the glass as half full, but chances are that's all we will ever see--or be.
Are you the kind of person who thinks that God punishes you when you get angry, forget to serve others, don't say your prayers, fail to read your scriptures, etc.? A glass-half-full person doesn't think this way. After all, the Zeus of Greek mythology that we often conjure up as our Heavenly Father does not even exist. The glass-half-full person notices the blessings that God gives to us every day. To see that he can't bless you fully unless you ask him for help, though, you become not only a glass-half-full person, but you'll begin to find over time not only that your glass is full more often than it is not. And your glass will grow larger and larger. Thus you become a glass-to-overflowing person.
The scripture teaches that
There is a law, irrevocably decreed in heaven before the foundations of this world, upon which all blessings are predicated—
And when we obtain any blessing from God, it is by obedience to that law upon which it is predicated.Glass-half-empty people are too preoccupied with their own problems to see what's going on around them. Glass-half-full people see the blessings all around. Glass-to-overflowing people obey eternal law and expect to be blessed even more. Simply asking God to help us accomplish what we're unable to do for ourselves, and expecting that help to come creates a synergy that makes our usually full glass grow even larger.