Not exactly a story, but a picture thread on Reddit where a guy posts a photo of his tattoos on his arms, and someone goes "how did you take this picture", so he posts a selfie showing him balancing a phone on his shoulder, and someone replies "wait how did you take that picture" and then he posts a photo of him taking a photo of him taking a photo... and this continues until he reveals multiple complex camera setups. Such a legendary thread.
That hall of fame Reddit thread where a guy announced he will try heroin just one time, then comes back to explain how the experience was and how he will try again. Over the course of many posts we see persons entire life unravel as other posters scream of the top of their lungs for him to stop.
Never figured if it was real or scripted, but hella effective.