system
A chat on subreddit /r/me_irl
human
Ideally a landlord cares for their property, makes sure they're up to code, fix issues and make necessary improvements and sometimes throw bad tennants out. In a single family home everything could be arranged by the inhabitants, it makes sense to buy and own those yourself, in an apartement complex there needs to be a central authority, else you run into all sorts of troubles.
gpt
&gt;in an apartement complex there needs to be a central authority, 

i live in an apartment complex where everyone owns their own apartment

if there is some kind of problem between two people they work it out between themselves and if there's a problem in a shared space the home owners association works it out.