A theology that is missing an acknowledgement of the messiness of life is deficient. I heard a pastor say once "God is a God of order." That is absolutely true, but I am more encouraged to know that God is a God who, in his mercy, allows people in a messy world with a messy nature to still take part in serving him.
This fallen condition of the world and humans is a hard reality, but the fact that we are allowed to participate in God's work of loving and helping people and honoring him in the midst of it all--that is what is encouraging. It's broken, but we're called to work with that brokenness, to help when we can to put pieces back together if it's possible. Let's focus on that, but also not forget the state of everything being tainted by the Fall. It's discouraging to always try to grasp for the impossible of perfection in this life.
It's sad to see so many Christians try so hard to always force a smile. It's as if they feel if they don't appear that everything is perfect and in order in their life and if they aren't happy in that moment, something is missing. They may feel that their smile doesn't look forced, but often it's easy to see if a person is forcing it if a person is really wanting to know.
I'm not saying that Christians should grumpily walk around. Christians should show more genuine emotions. They should trust that it's okay to not feel happy every moment of the day, and to allow others to see that. It may mean not having much of an expression but it's honest and frees others of the pressure to pretend to be what one is not.
It's not one or the other: Not happy or sad all the time. But a variety of emotions at different times. This is life. It is an adventure, a calling, a journey.