Postal - as in trying not to go

It occurs to me that all the barriers at the post office were created to ensure the safety of the workers. I had always wondered if it was a recognition of the fact that they all move so slowly and without regard for patrons' time (like most government workers).

I know that was a cynical thought. But it had crossed my mind a time or two as I waited in line.

Today as I examined the extensive covering keeping patrons from clerks - the only direct space open is where you hand back and forth money and stamps or receipts - I wondered: who keeps the clerks safe from each other?

Didn't going postal come from the violence they perpetrated on each other?