Your fingers ache from the constant play while sweat beads down your neck. Your eyes become unfocused, the colors and background blending together until they resemble something akin to a Monet painting. Clicking at a furious speed, you slay mob after mob, all the while watching the XP progress bar as it inches towards your final goal: the level cap. Time flies. You ask yourself, "Has it really been 13 hours? No, surely it couldn't have."
You open the drapes, staring at the stars and moon with a challenging look. Their day, too, will come. No matter. Neither man, murloc, nor the perpetual spinning of the earth about the sun will stop you this day ... er, night. Pixilated blood shoots from your prey. Their cries warm your soul, adding another notch to your symbolic belt.
Then, whether expected or not, it happens. Your character is engulfed a soothing light, and the game changes forever. You've done it. After days, weeks or months of work, you've hit the level cap. You can stare proudly at your once-lowly character and proclaim your might to all of Azeroth. You're the new tough guy on the block, and nothing can stand in your way.