Me too. When I am not fine, I will respond in a way that doesn't invite my depression into the passing conversation. I see that greeting as a convention of courtesy, and lots of people don't really want to hear a lot about how someone is doing. Of course, there are the exceptions.
yeah, I compartmentalize my depression for work and commitments. But it takes energy to do this! I also want to serve joy to people, and that feels good. The balance if it in energy tips on the depressive side far far too much....