"Buffy The Vampire Slayer" was a massive hit, but it's rumored that the show had some serious tension behind the scenes. For years, tabloids insinuated that on-screen besties Buffy Summers (Sarah Michelle Gellar) and Willow Rosenberg (Alyson Hannigan) may not have been so cordial when the cameras weren't rolling.

The problems began in 2002, when Gellar announced she was leaving the show in a cover story for Entertainment Weekly, supposedly blindsiding some members of the cast and crew. Years later, Hannigan added fuel to the fire during an appearance on "Watch What Happens Live with Andy Cohen."

Cohen, the king of spilled tea, asked, "Who was the most annoyed to be on 'Buffy the Vampire Slayer' by the end of the show's run?" "Sarah," said Hannigan, without skipping a beat. Though "Buffy" won 10 Emmy Awards over seven seasons, Hannigan claimed Gellar hated doing the show as early as Season 3.

Hannigan has since explained that she wasn't trying to shade Gellar, saying "She was the most tired because she worked the hardest" and calling her an "incredibly professional" co-star who "gave amazing television." In 2015, Gellar attended Hannigan's daughter's birthday celebration, so all is well between Buffy and Willow.