This type of game is the sort of thing that is super hard to explain to anyone that hasnt gotten it already. For instance:
This is the perfect spot for me to share this:
In Viscera Cleanup Detail, you step into the boots of a space-station janitor tasked with cleaning up after various horrific sci-fi horror events. Instead of machineguns and plasma-rifles, your tools are a mop and bucket. That hero left a mess, and it's up to you to deal with the aftermath.
It's a similar idea, high focus on satisfaction and the challenge of making sure you get all the details, though unlike Powerwash it's possible to screw up and make a mess again (if you've got a bucket full of bloody monster bits, gotta be sure not to knock it over... among other mistakes you can make, which are usually hilarious) and there's waaaaaaaaaayyyyyyyyyy more things involved in huge areas, and more mechanics involved (you've got tools specifically dedicated just to FINDING things you need to clean or fix, for instance) so individual "jobs" are very long and the pacing is slower. Your primary tool is a mop (though you've also got things like The Welder) and that does mean buckets, and carrying things around, and...
It sounds real stupid on paper, but, well... just look at the review count. Yeah. It's good. But I'd have a hard time trying to explain to you WHY it's so good.
I will say though, if you end up liking Powerwash, there's a LOT of games along this line out there right now. These are popular for good reason, even if I cant quite articulate that reason. Powerwash and also House Flipper seem to be the biggest ones right now.