Some things, like pizza and birthday cake, are best on the second day, eaten for breakfast. Here's my favorite way to enjoy that day-old pizza sitting in the box on the counter.
As soon as you roll out of bed, turn on your oven to 400 degrees Fahrenheit, so it can heat while you make coffee and wash the sleep out of your eyes. Lightly grease a cast iron skillet with some olive oil. Put a slice of pizza in the skillet. Crack an egg or two onto the pizza, nestling it into the toppings so it doesn't slide off (if it does, though, no big deal, that's why you greased the skillet). Put it in the oven, and cook until the white is just barely set, and the yolk still runny, about 7 minutes. The pizza will be hot.
Sprinkle some salt on the egg, and chili flakes on the whole mess. You can slide the slice onto a plate, or just eat straight from the skillet.