I'm not living my life in fear by doing that, I'm just aware of the fact from learned experience that people on meth tend to not react well to the fact that someone might be staring at them, and that there is also a certain type of person in public who tries to draw confrontations. This is being realistic. I don't stare at my feet at everyone who walks into the train, but there are some characters who you are wise to not do anything to draw their conversation, and its often pretty obvious who they are the second they step foot on the transit vehicle (e.g. the one looking for fights will be posturing the minute they are on the train and accosting people).