An unexpected apology

Recently after a break of a little over a year I rejoined a mentoring program that I volunteered with before the Little Man was born.  I took a break after he was born and had not seen any of the other volunteers since May 2012.  When I returned for my first day back I was met at the door by a volunteer who immediately recognized me and told me how glad he was that I had returned.  I was surprised by this and thanked him for the warm reception.  He then proceeded to tell me how he had been wanting to tell me for 2 years how bad he felt about a question he asked me when we first met.  We first met in September 2011 when I joined the program and evidently he asked me where I was from.  To me (then and now) that seems like such an innocuous question and I apparently answered it in just that manner by stating that I was "from" Oakland (where I lived at the time).  For two years he carried around the guilt of asking that question when what he meant was, "what is your background."  He was so passionate about his error that he told me if he had asked himself that question he would have wanted to punch himself.  I was stunned by both his passion and the fact that 2 years later he sought me out to immediately apologize.