I simply don't understand why anyone would send an unprovoked, nasty email to someone else. People on the internet have been pissing me off for nearly two decad

I simply don't understand why anyone would send an unprovoked, nasty email to someone else. People on the internet have been pissing me off for nearly two decades now, and I don't recall ever doing this. But like clockwork, someone does it to me every few months.