5. 2007-2008 Boston Celtics
The Celtics were outstanding in 07-08 but still haven’t received the credit they deserve. With an overall record of 66-16, they were consistently excellent all throughout the roster. Paul Pierce, Kevin Garnett, Rajan Rondo, and Ray Allen were destructive on the court.
Considering the Celtics went 24-58 the previous year, it shows how dramatic a turnaround this was. Not only was this a great individual season, but it was also one of the biggest improvements of all-time. They were able to carry their excellent form into the Finals, beating the Lakers 4-2.