I just find it intrusive.
They very kindly babysat the other day, we came back and he'd done a couple of (pointless) jobs in the house.
I find it slightly judgemental, like my standards aren't high enough for him so he just has to put it right.
Also annoying that he's wasting time that could be spent with his grandchildren meddling around my house!
My feelings could come from my childhood though, my grandparents moved country when I was 1, dad moved town when I was 4, and my favourite auntie moved country when I was 5. Been largely on my own ever since because I have lots of younger siblings who needed/received more attention.