Don't show up a month before harvest and tell me I gotta buy now or I won't get what I want, when I haven't even seen the stuff I just planted go through the combine.  Don't show up in a cheerful mood wanting to chat if I'm picking down corn at 1 mph.  Don't show up to ride in the combine and put your truck in the ditch and need a pull.  Don't send me an invoice for seed I never said I wanted to order.   Those are a few starting points that I have seen firsthand.