David Hartman, the first co-host of Good Morning America, closed each broadcast with the same benediction. In a 2005 speech that Hartman prepared for GMA’s 30th anniversary, he explained, “My daily sign-off line, ‘Make it a good day today,’ reflected GMA's values and the belief that each of us can affect our lives in a positive way.”
Message from Dr. B: The more common phrase, "Have a good day" implies that we can just sit back passively and a good day will present itself. I remember being young (very, very young) and hearing David Hartman say the above quote. I think it impacted me to be more active in my pursuit of happiness and achievement. So... Go out and MAKE it a good day!
I know you saw that coming.