Sylvester Stallone and Simon Sinek Agree: You Need a Work Rival 

Sylvester Stallone credits his epic rivalry with Arnold Schwarzenegger with driving him to greatness. A work rival can do the same for you. 

EXPERT OPINION BY JESSICA STILLMAN, CONTRIBUTOR, INC.COM @ENTRYLEVELREBEL

Sylvester Stallone and Simon Sinek. Photos: Getty Images

Back in the 80s and early 90s Sylvester Stallone and Arnold Schwarzenegger ruled movie screens in a series of action blockbusters. You might think Hollywood would be big enough for two muscle-y superstars to co-exist. But behind the scenes,........

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