This is sorta glamping-level, but if you're on a 2-3 day with a few people, you need Water. Lots.
My buddy has a subscription to 5 gallon water bottles, like the kind you get on top of water coolers in an office. He brought a couple out and we stuck this on top and set it all on the end of the picnic table - and it was SO USEFUL.
It was the hit of the whole campsite, allows you to dispense water for handwashing by yourself, just great.
Not a backpacking-tier item, but if you're bringing the squad out for a long weekend, good angle.