Bon Voyage, Mary Richards: When Mary leaves her TV station job for greener pastures on the Mary Tyler Moore Show, she drunkenly blubbers to her co-workers about how much she'll miss them. The classic show sets the stage for many boozy office party shows to come, complete with "truth serum" fruit punch, 1970s workplace attire, and sentimental speeches galore.

http://www.thedailybeast.com/blogs-and-stories/2010-12-04/top-10-best-office-parties-in-movies-and-tv-shows-the-office-bridget-jones-diary-and-more/5/