The phrase comes from Shaking Hands with Danger, a 1980 American industrial safety short made for workers handling heavy equipment. Its earnest theme song repeated the warning as a memorable chorus, and the film later gained a second life when it was featured and riffed on by Mystery Science Theater 3000. Clips and its song circulated online from there, and editors kept the short sung hook as a standalone joke. It remains popular because the old-fashioned, sincere delivery clashes perfectly with modern fail videos and casual risk-taking.