Prepare for It. This one is easy. All you have to do is smile and say "Thank you so much for your support. I've enjoyed my time here and I've learned a lot from you. Let me know what I can do to make the transition easier." Are you always going to get reaction number five? Probably not. But if you look for the signs, you can likely anticipate your boss' response, go into the conversation prepared, and come out stronger on the other side. Then, you can breathe a sign of relief and start looking forward to starting your new position.
The 3 points you want to get across can be accomplished in just a couple of sentences that include (a) your announcement that you are quitting, (b) as of a certain date, and (c) provide information about your last day.