How do I play being a musician to my advantage without coming off as an arrogant douche but avoiding the nice guy trap.

For example, I'm sitting in the common room in my university's residence playing piano and a girl walks in and says "Wow you're so good!" Instinctively I want to say thank you every time she says something along those lines, but that becomes incredibly redundant and boring to just thank her. How do I take advantage of this situation?