I have never witnessed a crime, but have seen some bizarre stuff like homeless dude walking a circle screaming at the top of his lungs "I'm going to cut you man! I'm going to cut you!" while flailing his arm out. Another fun one was an emaciated homeless dude stripped down to his tighty whities blowing huge streams of snot out of his nose onto the marble pedestal seating at the Embarcadero station. Another one was an unoccupied seat on a filled-to-standing-only BART train that was saturated by urine. A lady in a nice dress came onto the train and started to sit down until I grabbed her arm and said, "I think you will want to stand." At least half a dozen times in the last two years, the police have had a station locked down which stopped our train on the tracks. Last time was first part of this month up in Concord.
It has worn on me over the past three years until recently I started renting a car every week.