Phillipians 4:4 says "Always be full of joy in the Lord. I say it again- rejoice!"
Woo-Hoo! The Bible tells me directly that I am supposed to be joyful at all times, always to be exact. That doesn't just mean we should be joyful when everything is going swimmingly. It also means we should be joyful when the ship is sinking. Now that doesn't mean that we should be joyful because the ship is sinking, but we should be joyful because we have someone to turn to in or time of trouble. We are to rejoice in our relationship with God always.
Joy is our membership badge. Paul wrote this verse in Philippians from prison! He was sitting in prison and he was telling the Philippians to be joyful! He refused to let the prison and the conditions of prison stifle his joy in the Lord. When we are unable to praise God for the situation we are in, we can still praise him for being him. We can thank him for being with us in the midst of our trouble, and we can be filled with joy.