Politely you can say you are happy with your shots and your clients are too. How about bringing up the tpic of monitor calibration? Just use someone else's example and then ask her if she has ever had her calibrated.
Usually if I like my friends except 1 or 2 annoying habits, which most of us will have.. than I just ignore when they start annoying or try to divert the talk to some neutral topic.. Ignorance is bliss
... most of the times haha..