Being a head coach in the NBA is a ruthlessly unforgiving profession. Job security is an afterthought. Coaches have to prove themselves year in and year out, regardless of player injury or any other circumstances that are outside of their control.
The 2012-13 Coach of the Year results are already in, but that vote took place before the playoffs. George Karl of the Denver Nuggets did wonders with his team during the regular season and deservedly won the 2012-13 Coach of the Year award. Too bad the COTY award takes into account only the regular season, as Karl was thoroughly outcoached in the playoffs by Mark Jackson.
These five coaches were the best coaches in the NBA during the regular season, and then pulled away from the competition during the playoffs.