I like the friendly neighbor analogy urWorthy mentions. Sets the right boundaries that you want to have. If you're neighbor asked you what was overly intrusive because you're a bit distant one day, you'd probably just shrug it off, and say "nothing". If you're neighbor's clearly having a personal problem, you'd probably not intrude, but be available for them. It's a pretty good template for DB.
H: 38 xW: 38 M: 16 T: 18 S: 9 BD: 2/2012 W moved out 4/2012 D: 11/2012