So many people take the ordinary little things we do for each other for granted that it's nice to be reminded they are appreciated. It's like saying "thank you" when someone holds the door for you, even if they would have to practically slam it in your face not to do so.
I live alone, so, I don't experience this so much INSIDE my home. But, I always thank the grocery cashier for his/her help. They are only doing their job, but I appreciate it. I thank our apartment manager every time he does something nice for us, even if it's his job. It's appreciated.
I go to an archery range and ALL the maintenance is on us, not the Park or anybody else. When I help sweep up, the coach thanks me. When I see him doing something like that, I thank him. I thank the Park Maintenance people when I see them cleaning out the Park bathroom. It's their job, but the rest rooms sure do get unpleasant if they don't do it.
The more appreciated we make each other feel, the more we are willing to go out of our way for each other.