On occasion I will accidentally ignore someone because I didn't know they were talking to me. If other people are also around, I tend to assume it's not me that someone is talking to, because usually it isn't - like, in college, when I was walking to class, if someone would say "hi," I'd tent to assume they were talking to someone else.
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Yet in my new wildness and freedom I almost welcome the bitterness of alienage. For although nepenthe has calmed me, I know always that I am an outsider; a stranger in this century and among those who are still men.
-H. P. Lovecraft, "The Outsider"