The Happiness Equation:
We become happy when our life situation equals our life expectations.
Disappointed expectations:
We become unhappy due to disappointed expectations. When we're unhappy, we tend to allow life events, other people, and even our own mistakes to define us. All upset is because of unmet expectations. "Hope deferred makes the heart sick, but when the desire comes, it is a tree of life." Proverbs 13:12.
What you focus on is what you will find
Out of fear of disappointment, many lower their expectations, but ironically, this only leads to more and more disappointment. "For the thing I greatly feared has come upon me, and what I dreaded has happened to me." Job 3:25. Whatever you focus on is inevitably what you will find. Jesus said, "seek, and you will find" Matthew 7:7.
Seek godly counsel
It would do us good to seek advice from godly mentors (Proverbs 11:14), but remember that though man may fail us, we may find counsel in the word of God who will never leave us nor forsake us. (Psalm 118:8, Psalm 119:24, Hebrews 13:5).
Set your expectation on God through prayer
Our expectations are to be on God alone and we are to believe that He is a rewarder of those who diligently seek Him. (Psalm 62:5, Hebrews 11:6). "Whatever things you ask when you pray, believe that you receive them, and you will have them." Mark 11:24.
God answers prayers made according to His will
We can have confidence knowing that God answers prayers made according to His will. "Now this is the confidence that we have in Him, that if we ask anything according to His will, He hears us. And if we know that He hears us, whatever we ask, we know that we have the petitions that we have asked of Him." 1 John 5:14-15
God loves to exceed our expectations
God doesn't always answer the way we expect, in fact, He loves giving us even better than we expect. "Now to Him who is able to do exceedingly abundantly above all that we ask or think, according to the power that works in us" Ephesians 3:20.
All things happen for you, not to you
Also remember that all things happen for you, not to you. "And we know that all things work together for good to those who love God, to those who are the called according to His purpose." Romans 8:28.
Trade your expectations for appreciation
Discipline your disappointment by trading your expectation for appreciation. "Rejoice always, pray without ceasing, in everything give thanks; for this is the will of God in Christ Jesus for you." 1 Thessalonians 5:16-18. You can't choose your circumstances, but you can choose your reaction.