Ingratitude blind people's minds to the faithfulness and goodness of God in our lives. From the above passage, ten people were healed, and ONLY one remembered to return the glory to God. Luke 17:15-16.
Gratitude is an expression that emanates from the heart. The state of the willingness of the heart to open up to acknowledgment of a good deed, love shown, impressive effort from the other party, and every other thing to be thankful for determines our well and how sincere our gratitude will be.