Along the same lines, the crap that spreads like wildfire on Pinterest! Like making a homemade glow stick from Mt. Dew, baking soda, and peroxide or setting a dandelion on fire for a rainbow effect. No, there is no blue watermelon or rainbow colored owl. It's called Photoshop you gullible tit.DIY projects that pay no attention to safety.
Also the "Pinterest Fails" that involve people not following directions at all. Yes, your cake turned out looking like shit because you substituted half of the ingredients, then threw icing on it while it was still hot! How is that a Pinterest Fail? If you actually did what the recipe/directions said and taken your time you might have gotten a halfway decent result.