Indications that your architect didn't design enough space between your house and the house next door.

Just before bedtime, Mr. Tabubil was in the lavatory enjoying a quiet moment of philosophical contemplation. The world sorted to his satisfaction, he stood up and saw our neighbor looking at him out of his bathroom window - four and a half feet away.
            "Fine evening!"   The neighbor said, and smiled a big, wide, man-of-the-evening smile.
            "Lovely." Mr. Tabubil agreed.  And flushed.