Is photography the only gift you can give people where half the time they'll ask you for more? Give someone a print as a gift, and they might say something like, "Oh, this is wonderful, can you make one for Myrtle and Squatty too?" Or, "I just love this, can you make me another one, but bigger?" Or how about this: "Would you mind making me one that's exactly eight-by-ten so I don't have to get a custom frame for it?"
Which is a perfectly reasonable request, I suppose. In fact, many times when I give prints away, I make them eight-and-a-quarter by ten-and-a-quarter with a little air at the edges, so they'll fit in storebought frames.
Still, there's just something weird about giving photographs as gifts. I've never given someone a book for Christmas and had them say, "Thank you very much, now would you mind also buying one for my cousin Frank?"