Questions about the mechanics

Hi, sorry if this gets asked often but I couldn't find anything when I searched. There's a few game mechanics I'm confused about.

1. Does painting do anything? It sounds like it didn't have any actual effects from posts I see from a year ago, but I couldn't find anything recent.
2. Does cleaning trash off the floor do anything? Again, I get the impression it doesn't actually affect the customers to have trash on the floor as long as you sweep it.
3. Does cleaning areas other than the shop and toilets do anything?

Thanks to anyone who can help me with these!