What is with these people? The occupants of Monica & Rachel's/Monica & Chandler's aprtment hardly lock the door, and they -- and across the street, U.N.G. and then Ross -- don't keep the drapes closed! Don't they believe in keeping out intruders and peepers?

When you're writing a tv show, for the sake of pacing and timing you don't have the characters unlocking doors and such. This is why almost every show just has the characters walking in without knocking or anything. To do anything else would upset the flow of the scene.

There are plenty of people across the street from me who don't keep thier curtains/blinds closed.

Some of them really should...