Hypoglycemic emergencies have to be my favorite. They are one of the few calls where you can see the fruit of your efforts. Unconscious? Start an IV, give some D50 and they wake up. 'Semi-conscious' and fighting you like you're trying to kill them? Wrestle them, somehow start the IV (with or without the aid of Glucagon), then give some D50... they wake up and become your best friend once they realize what happened. Hypoglycemia is one of the only things that we can actually FIX in the field, and is a true emergency that can quite rapidly lead to death. If fixing that doesn't make your day or week, I don't know what will.
What are some of the calls you like to go on?