...Since God chose you to be the holy people he loves, you must clothe yourselves with tenderhearted mercy, kindness, humility, gentleness, and patience. Make allowance for each other’s faults, and forgive anyone who offends you. Remember, the Lord forgave you, so you must forgive others. Above all, clothe yourselves with love, which binds us all together in perfect harmony. And let the peace that comes from Christ rule in your hearts. For as members of one body you are called to live in peace. And always be thankful.
Being thankful doesn't mean that we are in denial about our situation, it is really about humbling ourselves and trusting God to work things out for us in His way. We give thanks in the midst of the situation, (not for it) and believe by faith that He will give us wisdom, guidance, and peace until we get through it, knowing that He always has our best intrests at heart.
There are many who will say that they have absolutely nothing to be grateful for, and are angry at God for the way their lives are going. The Word says that people would be increasingly ungrateful in the last days..