I was given a near final collection of sayings and doings of the Prophet (عليه الصلاة والسلام) on the topic of smiling to look over around a week ago. I started going over it today and in doing so noticed this verse (53:44) mentioned a few times...
"And it is He (Allah)
Who brings about laughter
and brings about tears."
... and then irony of ironies guess which Surah the Imaam recites just now in Eisha prayer? Yup! Never noticed it before but'll probably now never miss it, alhamdulillah.