I take it you've never had to ask strangers in your company for something. It's just like meeting someone from the public, if you have to meet someone from another department for the first time. (I've discovered, if you need it today, a personal request works better than an e-mail, and if you need to send a second request, in person works better than a phone call. "Hey, Bob, I just discovered that there's a problem with the XYZ report, and I need this information _yesterday_ so that I can get corrected numbers in time for the monthly financial statement. Can you help me?")