Who's our biggest rival now?

With the game vs the Warriors tomorrow I was wondering who you guys think our biggest rival/rivals are.

Before 2015 I think it was always the pistons or bulls.

Obviously with 4 back to back finals series with the same team would push things up tremendously with the Warriors

And the celtics just being who they are and the battles with them 1st lebron stint I think about the as well.

Who would you guys say?