You'd expect two players in a competitive tennis match to grind out every point, battling to the end.
Not American tennis player Jack Sock, playing against Australian Lleyton Hewitt during a Hopman Cup match on Tuesday night.
Hewitt served, with the umpire calling out on the ball. Sock decided to intervene, saying, "It was in, if you want to challenge it," to a rather bemused Hewitt.