Playful decor buff is driving me mad

@akihamuko. Take a look at the thread linked above and see if you have any of those listed items in your living room. 

You can also take a screenshot of the playful mood message, as well as your sims' living room from different angles and attach to your post, and I'll try to help you look for it. 

What careers are your sims in? A lot of reward items give off auras. Trophies too I think, and what they do in the living room matters as well. 

Are you sure you don't have the clay? You can leave your sims on high autonomy, they are bound to go for it eventually if it's there. 

If you click on any object in the room from within build mode, the object info, including if it emits any auras, is listed in the lower right corner.  

Also put up your walls if it is a wall decoration creating the mood.