Is happiness a choice? I will say, yes. If everything in our life is going along fairly smoothly and we hit a bump in the road, like a flat tire or an unexpected bill then, yes--Most of us can choose to be happy. Some of us have walked with the Lord long enough to know that He will carry us through these days of trouble.
But what if a person struggles with depression? Is it fair to say happiness is choice? A person with debilitating depression lives day to day with a feeling of physically carrying a burden on their body. They really do feel like they are wearing a lead blanket.
Is it fair to just tell this person, who may be a Christian that happiness is choice? If they had cancer, would way say "praise God you can choose to be happy"? No, most realize how very insensitive that would be.
What about sin? Is sin a choice? Again, I will answer yes. If we are faced with a choice in our life to lie or cheat on our taxes then I would say, YES that is a choice. But what about the person who is bound by sin? What about the person who craves to commit a sexual sin or is driven by greed? Even if that person is a Christian they may feel completely helpless to their fleshly desires.
When it gets right down to it, if a person--Christian or non-believer-- is bound by sin or sickness it is them same result. They will not see freedom just by choosing to be free.
What will bring freedom, you may ask? Freedom comes only one way. Healing comes only one way. Believing in the finished, complete and perfect sacrifice of our Savior Jesus Christ. He came to earth as a baby -- 100% man and 100% God to die a death meant for a sinner. He became our substitute for sin. He took all the wrath that was due to humankind so that we could have His Righteousness.
Many accept the fact that we need Jesus to save us from our sin, but how many are trying to do good works to try to please God enough so He will heal or deliver them completely out of their sinful lifestyle?
I did this for decades. I thought if I prayed enough, or served enough or gave enough of my time or money then it would get me ticket for my healing. I was jumping through hoops trying to prove my love and dedication to my God when the only thing He desired was for me to BELIEVE that Jesus already did everything for me.
It's not by might nor power but by My Spirit says the Lord...this mountain of sin or sickness or lack shall be removed. As New Testament BELIEVERS it's not obey and be blessed but BELIEVE and RECEIVE!