Here's my opinion - happiness is an emotion based on circumstances. We should strive for joy, which is deep and abiding. Many times, I do not feel happy (even if things are going well!!)
but the joy is always there. It's a deep down, reassuring feeling that, in the end, everything will be as God has promised. It's the only way to get through this painful world. If we can pass it on, even better! Many people spell joy this way - Jesus, Others, You. Keep things in that order and we keep our joy.