That happened to me this a.m. at sunoco!!! I randomly greeted someone --took a few seconds.....but they didn't reply...i simply assume they didnt understand me......I sort of just shrugged it off....like whatever! If I don't understand someone I tend to not respond because I don't know what was being said...tricky situation! When people speak to us...why don't we as stutterers deliberately ignore them...saves us the trouble of communicating back and stuttering while doing so!