The relationship between team-mates is a special bond. In fact, it's often said to be the reason former players miss the game so much.
However, as much as the time spent together behind closed doors can strengthen that bond, it can also sometimes prove a little bit too much at times.
Just ask Cristiano Ronaldo, who kicked out in frustration following some playful banter with close friend Marcelo during a training session.
During the exercise, in which Los Blancos players rapidly passed the ball round the circle, with piggies in the middle attempting to rob their colleagues of possession, Ronaldo then took it upon himself to launch the ball into the stadium.
Ronaldo, usually so cool under pressure, then told a local journalist, "You have material to talk about during the next two days".