The 20-time Major champion Roger Federer has been a role model for many tennis players over the last 15 years. Like all the other competitors, Federer has had some dark moments in those most challenging moments throughout the years.Still, he is usually calm and collected on the court, focusing on tennis and the rival on the other side of the net. That was not always the case, though, as it would be hard to recognize Roger for his behavior in the closing stages of his teenage years!The Swiss could not keep his temper down right from the first competitive matches in juniors, throw …