I wanted to try my hand at creating custom traits and came across the Sweet trait here on MTS, but the trait seems to have been not redone after C&D seems to have broken custom traits. I figured I might as well try to make one like this. For some extra fun, all the buffs are song titles.
Sweet trait (Social Trait)
"These Sims are always kind and cheerful, often having no greater joy than to make other people happy. They also tend to have a sweet tooth."
Baking Whims - All
Be Friendly Whims - No 'Be Mean', no 'Be Mischievous'
Whim-set New Romance - No 'Be Mean'
Whim-set New Romance_Plus - All (Kiss; Make Out)
Whim-set Partners - No 'Divorce', no 'Break Up'
With my own testing, I've noticed a few things.
There's an immedate and constant +1 Happy from having the Sweet trait. (I'll remove this)
I've managed to have the "Sweet Thing" buff appear (though I forgot to add an icon for that... oops) and the "Makin' Love" from Woohoo.
The interaction buffs have not appeared, despite having done stuff like Hugging Sims and similar.
...and I just remembered, hitting the screenshot image in-game removes the entire UI; so none of my 'proof it works' pictures show the buffs... I'm a genius.
PS: Finally got around to getting screenshots of the trait in CAS and some of the custom buffs.