Pre-intermediate

One of my favorite economists, Dan Ariely, tells this story about a locksmith. When the locksmith was new at his job, when he was an apprentice, he took a really long time to open a lock. And people saw him working away, struggling, really having a hard time. And often they'd end up giving him a tip. But then when the locksmith got better at his job, when he got so good at his job he could open pretty much any lock in just a minute or two, then his customers started complaining. They were like, you want $200 for that? This took you, like, 30 seconds. And you can see why, right?