In many different situations...
Of course, doing little good deeds like this may seem like they're a good thing, after all, how could helping someone without their knowing be harmful? It's true, many situations exit in which you could do a good deed someone without their knowing so. In many outstanding cases this is a good thing, but people sometimes fail to realize that this could also be a bad thing.
"Wait, why did you do that?"
If you're on the receiving end of this question after having done a good deed for someone else, there's a chance you just messed something up. You never truly know what a person is intending for any sporadic situation, especially in their own residence.
Most of the time, they're small things and are easily corrected. However, there are those few times you do something seriously harmful. "Well, the papers were in the paper shredder bin..."
It's always better to ask first when it comes to someone else's things. Don't get grabby fingers and start doing things for them like you're at your own house. Even if they forgot to close a certain door, you never know if there's a reason. "Mind if I shut this door?" "No no, I leave it open for the cat."
I'll use a crude and specific example: When I join Minecraft servers and see that people have left their doors open, I don't shut them on their behalf. I don't know why they left their doors open, but I know that they did; perhaps they had a good reason? I don't know. If it were my door, I would shut it, and while I might forget to shut my own door from time to time, it would be my own fault if a creeper walked in and blew it up. I'm learning to keep my hands to myself, so I'm applying the concept to all aspects of my life, even though It's just killing me to go shut the door for them.