Does any one else have a pre-occupation with not lying? I absolutely hate lying to other people. If some one tells me they love me, and I don't feel it I wont say it back. If I absolutely abhor spending time with someone, I tell them to fuck off. That's not to say things never change, in the "I love you example" of course I'd say it when I feel it.
This bar on lying has gotten me into a lot of sticky situations, but I still can't bring myself to lie to someone even if it's to make them feel better. Or maybe a better less egotistical way to put it is that I refuse to pretend to posses feelings that I don't.
That's not to say If some one says "I miss you!" I'd respond with "I don't miss you!" I'm more likely to change the subject or respond with something abstract like "<3"
The only exception I've found is generally speaking I have a really hard time not saying "I missed you too" When people say they miss me... Which bugs the shit out of me since I rarely if ever miss anyone.