I didn't cuddle last night just to illustrate this. This is at about 19 1/2 hours after cuddling:
Happiness Solid @ 74%:
The funny thing is, two of them have gained happiness from 74% to 75% since I first logged on. (I was waiting to see if it dropped lower.) I'm sure they're happy to be getting a good night's sleep!
Hmmm... a bunch of them dropped down to 74% when they hit 10% hungry. Not unexpected, but I didn't know there was a line there.