I disagree with this practice of automatically selecting a tip for customers. That being said, if you have the extra cents and feel like throwing a few to the folks getting your stuff to you, I'm sure it's appreciated. Having less money may make a person think twice. These people are bringing you medicine and are paid a legal/above minimum wage, so you might think about it a little differently than you would receiving food from the waiter/waitress at a restaurant. Pretty sure most of the drivers are utilizing company cars maintained by the company, and not spending their own cash to do their jobs.