Is that, unlike most sitcom neighbors, he rang the doorbell before entering the apartment. It's silly when characters just barge right into their neighbor's homes. Don't get me wrong, it happens on some of the greatest shows. That's the thing I thought about when watching "The Joey Bishop Show" on DVD. Of course, Jillson didn't seem like the kind of character to just force his way into the Barnes' home.

...Mr. Jillson was the maintenance man! They NEVER barge into people's apartments without a reason! Jillson had good taste in not entering Joey's apartment until knocking (or "ringing the bell"). It was AFTER he came in that
things began to "unravel"!