Roy Keane is one of the best footballers in history, but .......
http://www.youtube.com/watch?v=p_st29mlQwU
for those who don't know, that challenge ended Haaland's career. From wikipedia:
Håland is often remembered for Roy Keane's feud with him. In 1997, when Manchester United were losing to Haaland's Leeds United team, Keane attempted to tackle Håland late in the game. In the process, Keane injured his anterior cruciate ligament. As Keane lay prone on the ground, Håland criticised Keane for the tackle and suggested that he was feigning injury to avoid punishment. Keane was booked as he was stretchered off the field. Three and a half years later, in 2001, Keane fouled Håland, high up on his knee. Initially, Keane was simply fined £5000 and received a 3-match ban. However, in his biography he admitted that he wanted to "hurt" Håland as revenge for the taunting he received years previously. After this revelation, Keane's received an additional 5 game ban, and £150,000 fine. Håland retired through injury in 2002