William Shatner and Leonard Nimoy
Yep, the two iconic Star Trek actors have beef with one another! Truth be told, William Shatner wasn't the most popular guy on set, but he and Nimoy really had it out. According to most people you ask, Shatner was jealous of how fans adored Nimoy.
Will Smith and Janet Hubert
Will Smith and Janet Hubert were on The Fresh Prince of Bel-Air together. Hubert's issue with Smith started early on in their career together as she felt that Smith failed to help negotiate their salaries. Not only did she not appreciate his failure to help negotiate, but she didn't like his reaction to the accusation which was just a simple shrug.