Typical scenario at work.
Client, "Stuck injector? That can't be what's wrong with it. Are you sure it's not the spark plugs like I thought? I was pretty certain that's the why it was running rough when I dropped it off for you to look at."
Me in response, "Well, I did show you what I'd found inside your motor, and what I feel will repair the problem. Furthermore, I had the spark plugs out, inspected them and they appeared fine. Diagnostics show you're getting signal and power to them. I replaced them anyway for good measure because you requested that and it didn't help your situation."
Me internally, "IF YOU KNOW WHAT THE MOTHEsmurfING PROBLEM IS, WHY ARE YOU TAKING THE CAR TO A GARAGE?!?!? IF IT WAS JUST SPARK PLUGS YOU WOULD HAVE DONE IT YOURSELF!! LISTEN TO ME, YOU $&%!@& MORON."![]()