I would recommend reading this article by Jim Elliff discussing the connection between happiness, joy, and Christmas. He comes at it from an evangelistic slant and I think might be helpful both for our own souls and as a something to share with unbelievers we know. Here are a couple of highlights.
Can tinsel and presents, carols and candy really bring happiness? Not often, and not much. And if our happiness is based on circumstance, is it a true happiness? Isn’t it just a playful escape, a temporary delusion? Does a little thin paint on the outside eradicate the rust beneath? Do cosmetics on a corpse make the death go away?
I think the diversion is worth something, mind you, But when the reality is so strong, do we have the right to call even Christmas a source of true happiness?
This “reality” is much more troubling than the list mentioned above-the depression, sickness, sulkiness, and aggravations. The reality for a person without Christ is a permanent state of non-forgiveness, alienation from God, separation from the true people of God forever, and hell. Those are the matters that make happiness hard to come by and what makes laughter so fugitive for the thinking person.
and
If a person is related to God through His Son Jesus Christ, then joy, that deeper happiness that is more than a facial characteristic, is a birthright blessing. The true Christian should be joyful because his sins are forgiven, his place in heaven is secure, his life is in-dwelt by God’s Spirit, and he has an open door to God’s throne room. No matter what happens, he always has reason to rejoice because the big things are taken care of, and the Spirit in him promises to help him through all the rest. In a word, his joy is not based on circumstance, but on huge unchanging facts and an even bigger God behind the facts.