Honestly I think the loss of humans just talking to others is the primary cause of most of our modern problems.
I have also however, never had a good experience knocking on neighbors doors. If someone is being incredibly inconsiderate, like say blasting music at 1am, then why would they be more considerate if I knocked on their door?
A fully grown adult living in an apartment complex should be able to know that sound travels, they have already made the decision to be inconsiderate. Are they supposed to change their mind because I appeal to them face to face?