You must say "Thank You" on the grayest days. If a gray day is not one of thankfulness, the lesson has to be repeated. Not to everyone is it so. But only to those who ask to serve Me well.
Origins of this reminder:
Thoughts from the Two Listeners after reading:
"Fear thou not; for I am with thee: be not dismayed; for I am thy God: I will strengthen thee; yea, I will help thee; yea, I will uphold thee with the right hand of my righteousness..."