Have a *Happy* Day

Cecil’s column: Who invented the smiley face?

The slogan going with the smiley face is always quoted as “Have a happy day” in the column. I don’t remember that, although I was in high school when the fad started. But later, I heard it as “Have a nice day.” Anyone know when or how the slogan changed? Or am I just mixing up a catch phrase from later on with the original slogan? I know I’ve seen stuff with the smiley and HAND, though.
Edit: I wonder if Harvey Ball’s gravestone has a smiley face on it?

Gahk! I came here to post that very thing. Guess I’ll just stick around to see.
In the linked column even Unka Cees says: “IF I SEE ONE MORE FREAKING SMILEY FACE I AM GOING TO THROW UP. Thank you, and have a nice day.”

It was remembered as “happy” as early as 1977. I’m not sure what it actually was ca. 1970.

Frankly, my day would have been happier and nicer if someone had explained to whichever of Cecil’s minions never learned distinguish “principle” from “principal” that there’s a quite simple mnemonic to help you: if you’re using it as an adjective, then it has to have an “a” in it; if you’re using it as a noun, remember that the principal is your pal.

–Balok, the last man on earth or in the First Federation who still cares about spelling and grammar

omg ur rite u roxxors

Better lay off the tranya, man.