He really never went postal on me, but when I did take him an order to fill, he'd call me and say that the product wasn't in the location listed. I'd look at the Receiver he gave me for the locations he listed that he put the incoming stock and told him "that's where you put it and that's the location I put into the computer." He was a nice guy, but I was sure glad to see him go!
Every job I had in my life always had several co-workers who would rub me the wrong way, finally got into welding, good profession you work alone, don't have to worry about co-workers unless you really want too which I never did....