Two men look at the same scene:

(J.R. Miller)

"Be joyful always!" 1 Thessalonians 5:16

"In all our affliction, I am overflowing with joy!" 2 Corinthians 7:4

Thankfulness or unthankfulness is largely a matter of the attitude of our heart.
Two men look at the same scene:
  one sees the defects and the imperfections;
  the other sees the beauty and the brightness.

If you cannot find things to be thankful for today, and every day — the fault is in yourself, and you ought to pray for a changed heart — a heart to see God's goodness and to praise Him.

A joyful heart transfigures all the world around us! It finds something to be thankful for in the barest circumstances, even in the dark night of the soul. Let us train ourselves to see the beauty and the goodness in God's world, and in our own circumstances — and then we shall stop grumbling, and be content and thankful in all situations.

"A happy heart makes the face cheerful!" Proverbs 15:13

"The cheerful heart has a continual feast!" Proverbs 15:15

"A cheerful heart is good medicine — but a crushed spirit dries up the bones." Proverbs 17:22