I have. I was in graduate school and I was getting feedback on a talk I gave. Colleague: You say “um” and “uh” too much. Me: Thats because I have a stutter, it helps me ease through a block. Colleague: I never heard you stutter. Me: It varies on situation and word. If I have to say n-n-n-neuroscience; see? It comes out. Colleague: That makes no sense. Why would you stutter on one word and not another; the brain doesn’t work like that. Just work on your presentation skills... KAY.