In 2015, a 22-year-old Australian made $105,000 in 10 days from a $9.99 glitter envelope. He spent most of those 10 days publicly begging people to stop giving him money. Mathew Carpenter built Ship Your Enemies Glitter as a side project and expected to maybe cover the domain cost. Within four days the site had 2.5 million visits and more than $20,000 in orders, and he was drowning in fulfillment. So he posted on Product Hunt. "Please stop buying this horrible glitter product. I'm sick of…