They're definitely an activity, because even when the sim is practically dead from starvation, it can't find anything better to do than play with them!
Sims obsessing over sprinklers 24/7 is a real bother. I've been trying to work the 'Perfect Garden' challenge. With lots of plants. If I install sprinklers to decrease 'tend garden' time, my sims spend the rest of their time, day and/or night playing in the sprinklers. If I don't give them sprinklers, then my sims spend a lot more time watering and the plants seem to suffer in spite of all the watering by hand.
Oh, and they have plenty of toys and other stuff too.
So here's me question. Does anyone know if this is definitely a glitch (to be fixed someday)? Or do my sims obsess over sprinklers because of a trait characteristic or perhaps something else?
p.s. I've even gone so far as to place a (locked) gated hedge around the entire garden. My sims still get the sprinkler thought bubble and grumble/stomp their feet because access to the sprinklers is blocked (locked off).
I know, I know... I'm mean!!! But it's my way or the high way. After all I'm a grumpy ol' grandpa man.