Shouldn't our actions and words reflect us? Of course.
But I don't think the author had this in mind. I believe the words "what reflects us much" refer to those things that we do in an attempt for self-aggrandizement. I know I am guilty of this. Don't I want others to think well of me? Of course, I do. Ironically, in my self-aggrandizing attempts, I do the opposite. Rather than thinking well of me, others see my pathetic attempts for what they are.
As for the last part of the quote "accomplishes little," I have to ask myself if I were trying to accomplish anything at all with my boastful words. Sadly, the answer is "No." At least, nothing of worth.
Joy for today: reflecting little and accomplishing much.