This joke is original. Every now and again a US Postal Service employee or ex-employee gets a gun and kills a few people at his work site. Pundits are beginning to wonder why this happens so often. I think they're looking at the problem the wrong way. The US Postal Service is an immense enterprise. Anything, including attempts to shoot a half dozen co-workers, will happen rather often. The pundits should wonder why USPS massacres only happen once or twice per year. Actually, USPS employees shoot up their offices a half dozen times per year or more. So why don't we hear about it more often? Because these are Postal Service employees. The bullets take weeks to reach their destinations, allowing plenty of time to dodge, and many don't make it at all.
(From the "Rest" of RHF)