rather than going through the faff of sending a formal response to every party invitation? Or have I been terribly rude in replying in person and by email or phone? I do always let the hosts know whether or not I can make it - it just seems absurd to send a card to someone when I will be talking to them anyway. If it was an occasion like a birthday, wedding or christening that I could not attend I would send a card.
It is just that the RSVP thing seems to wind people up so much...