Neighbor woes(not mine, mayb my neighbor's)

Last week, while removing my shoes after coming from a stroll, I noticed that my neighbors have left their key bunch in the key hole itself. Coming to these neighbors, they are a Mallu family, one guy with a wife, mother and two kids. I never saw his wife or the second kid. I give some chocolates to the elder son(who's around 3 years old), when he's playing in the corridor with his granny. However, there's no more relation between me n them except a casual smile or a "hi".

So, after looking at the key bunch, being a good neighbor, I knocked on their door. After a moment, the wife opened the door with the door latch ON and was looking at me with a scowl on her face. She was looking at me as if I entered some restricted territory. I just told her that they left their key bunch in the keyhole, which she pulled with some mighty force and slammed the door shut without even looking at me. Poor me, was expecting a thank you from them, if not a lunch invitation in the weekend(these are termed as Bachelor Woes). I was ashamed by this lady's behavior and then being free for some time, I started analyzing what might have went wrong.

1. Maybe her husband didn't cook lunch well(too much salt or no salt).
2. Maybe the chocolates I give to her kid are expired or they have worms in them(I hope you remember the Cadbury Dairy Milk case).
3. Maybe her elder son, who started going to nursery, brought home his girlfriend.
4. Maybe my shoes, which I keep in a shelf next to their door, stink a lot.
5. Maybe she felt bad about me knocking the door, when they had their new calling bell installed that very day.
6. Maybe she's a victim of the sound coming from my home theater(most likely).

Well friends, did anyone of you face some embarrassing situation like mine?