My personal Mantra, which I used to use as a signature, is:
"I am soooooooooo happy - How on EARTH could I be otherwise?"
Say it enough, and I'll be danged, it works!
Then I read a quotation by an eminent 19th Buddhist author, which I had previously been unaware of...
"There is nothing clever about NOT being happy."
So you see, it's nothing new, then......!