My life would suck without you
One that I can think of is when you put a Pokemon in the Day Care and then go to one of the sand hills that you need the Mach Bike for and then go to it so you can get up and fall down again. You then way down the up button on your game so it goes up and down automatically. Because each time you go up is a step, your Pokemon get raised in the Day Care. It works in R/S but I'm not 100% about Emerald.