Today it was a woman standing at a railroad crossing screaming at every car/truck/bike that used the crossing:

I'M GONNA KILL YOU!!! I'M GONNA KILL YOU!!! I'M GONNA KILL YOU!!!

She had a bike with her loaded up with what I'm guessing was all of her possessions.
From a couple hundred feet away, I called the local PD, and loitered until they arrived.
Apparently, she really didn't want people driving over her railroad tracks.