This is a suggestion to anyone who relies on others to get their own jobs done: Be Kind.
I work in an IT support department, and the number 1 issue that makes working in IT frustrating are the users who call up and demand that I hook stars and bring them down for them to use at their whim. And do so in a condescending or cruel fashion.
Sir or Madam, you do not seem to understand something very pivotal about our relationship: The very same abilities that allow me to help you with your issue also give me the knowledge to make your computer world a world of pain.
Now I would never do that, but since I could theoretically, you would think it would give you an incentive to at least be kind and polite. I know you are having issues, and I didn't cause them, so there is really no reason to treat me like I'm something you found on the bottom of your shoe, especially since i can erase your entire hard drive in about 30 seconds.
Again, I would never do that, but I am also not the only person with whom you should be polite.
Plumbers, electricians, contractors, police, firefighters, anyone on whom you rely for your daily comfort, protection, or just general ability to function should be treated with, at the very least, politeness.
Really, there is almost never a reason to ever treat anyone poorly. A gentle answer turns away wrath, and it is possible to be kind and strong/assertive.