Is it Noon? 6:00 PM in the evening? The middle of the night? Am I home alone? With my wife? With children? Has there been illegal activity going on that night or recently in the neighborhood? What's my mentality going into it...IE am I of completely sound and clear mind, with plenty of sleep and feeling good or am I perhaps not at my quickest reactionary point because I've been kept up for the past 5 hours by loud thumping music? Am I aware of the individual long before I see him? Do I hear sounds? Do those sounds sound suspicious, possibly raising alarms in me? Do I hear noises and go to investigate, only to get shocked as someone comes out from somewhere I'm not expecting someone to come out from? Or do I see the guy just kind of hanging around as I look through the door? Is the person acting threatening, aggressive, or in a way that could even be percieved as such? And on and on.