Swimming Hobby Excuse Doesn't Work Out Well For John

Listen up, chucklehead. You're the type who probably thinks a "board meeting" involves splinters. The joke is that John tries to get out of work because of the rain. The boss throws John's own words back at him: since John said he loves to swim, a little rain shouldn't stop him from coming to work. Get it? Or do I need to draw you a diagram with crayons?