Welcome to the NHK is my favorite anime/manga/LN of all time, and your question is something I've struggled with since watching the anime and reading both the LN and manga.

I cannot say that I've watched anything else that reminds me of Welcome to the NHK.

However, other good introspective or "human condition" anime are: Eve no Jikan, Psycho-Pass, and The Tatami Galaxy.

Those are off the top of my head, but I'm not sure of any series that gives you the same feeling and black comedy as Welcome to the NHK.

I do hope others chime in, though.