Im avoiding it most of the time to add some "mystery" but after a while I figured I lost the idea of what actually to say. Last 5 times or more when a girl asked me "What you up for?" or "What you doing?" I don't answer the question and carry on with the last topic we were on or change the subject and continue with random talk about her/something else. The result is fine as the conversation carries on (she doesn't care what do I do anyway) but Im not sure is that the right path to take.

Thoughts?