Sportsmanship in football. When to kick the ball out, when to give it back to the opposition, what to expect from players - it's a bit of a grey area.
Leeds United scored against Aston Villa on Sunday when players had stopped because a man was down injured, prompting an angry reaction from the Villa players. Leeds boss Marcelo Bielsa told his team to let the opposition score a goal back. The game finished 1-1.
But the actions of both sides had plenty of people debating the obligations of good sporting behaviour.
So why not test your memory of similar incidents - celebrated and contentious - with our quiz?