Once upon a time I was a younger engineer in a new plant - doing business cases and analysis. While talking to an old buyer I was amazed at how nicely he treated me - in reality most just would treat me like crap. When I pointed this out to him he said, "someone a long time ago gave me the advice that I should always treat you young guys as best I can because someday you're going to end up being my boss and I don't need to burn any bridges."

I have used that advice many times.

It applies to negative selling. Never negative sell. When reps come in to talk to me if they sell their product by attacking other product....I walk. When they come in 6 months later repping the other product and now try to sell it to me....I laugh.