It’s always good to be right, right? Here is the solution image to Be Happy. The clue-explainer video follows, then a few words about the theme.

I wrote this in November. It’s a pangram.
There is a Nina in the perimeter: WELL THAT’S WHERE IT ALL FALLS DOWN, which comes from a conversation between Arthur and Slartibartfast –

Slartibartfast: … What does it matter? Science has achieved some wonderful things of course, but I’d far rather be happy than right any day.
Arthur: And are you?
Slartibartfast: No. That’s where it all falls down of course.

…from which you can see that I actually got the quote wrong, as there’s no “WELL” in there.
I’m annoyed with myself, but Oh Well, as Fleetwood Mac would say…

EXCEPT, WAIT! – The text I quoted above is from the original radio series, and the book too. I no longer have the album to check, or the TV series to hand, but in the IMDb page for the film there’s:

Slartibartfast : Ah, no.
[laughs, snorts]
Slartibartfast : Well, that’s where it all falls down, of course.

So, in a way, I’m right after all. “Of course”. I’d just rather Be Happy.