Here’s a social media challenge restaurant workers will love. How does it work? Well, no detergent pods, no buckets of ice or boiling water are involved, thank goodness. The challenge involves leaving the server a tip that is the same amount as the bill. A 100 percent gratuity! That's highly unusual, but always welcome. Diners everywhere are tipping 100 percent on their meals and posting photos of their receipts on social media using hashtags like #loveyourserver, #payitforward and “#tipthebillchallenge”.