Sometimes worship and thanksgiving can be a sacrifice. That may be because we are down or depressed or things aren't going all that well for us. Maybe hardship or tragedy has struck our lives in some way and we don't want to thank God.
Yet the Bible urges us to give thanks to the Lord. Psalm 106:1 says, "Praise the Lord! Oh, give thanks to the Lord, for He is good! For His mercy endures forever" (NKJV). We are told in Colossians 3:17, "And whatever you do in word or deed, do all in the name of the Lord Jesus, giving thanks to God the Father through Him" (NKJV). And Hebrews 13:15 says, "Therefore by Him let us continually offer the sacrifice of praise to God, that is, the fruit of our lips, giving thanks to His name."
We are not told to give thanks to the Lord because we feel good; we are to give thanks to the Lord because He is good.
As we approach God to ask for new blessings, we should never forget to say thank you for the blessings already given. We should be just as definite in returning thanks as we are in requesting help. But many times we aren't. We are quick to ask for help, but we are slow in giving thanks.
Answer taken from Give Thanks ... in Everything by Greg Laurie. Click here to read the article in its entirety.