> I think we are all programmed to respond well to any courtesy, no matter how indirect.
I once read a book called "The Media Equation" that argued humans' social cooperation/courtesy instincts are many thousands of years old, while computers are very new (the book was written in 1996). As academic HCI researchers they'd conducted many experiments, providing evidence for this, which is why it's a book, not a paragraph.
What I found fascinating about this book was you could see how their findings had directly translated into Clippy in Office 97. You close 'Clippy' and it waves goodbye instead of disappearing immediately? They had research findings saying that was perceived more favourably.
And everyone knows how well-received clippy was :D
Clippy became infamous because it couldn't actually do anything it claimed to do. It also seemingly broke the courtesy guidelines by appearing uninvited and stealing focus.
And I would say in its case, there was great synergy between not doing anything and appearing uninvited. Two negatives combining to produce an overwhelmingly greater negative.