Tried to pick a film that many of you may not have seen and one that is worthy of checking out, the film in question Crime d'amou (Love Crime). This examination of the work place focuses on the conniving and manipulative personalities of the ambitious. Kristen Scott Thomas is at her very best in this French thriller. There was a remake (directed by Brain Da Palma), but I haven't seen it.
My next choice is one you probably have seen. Office Space perfectly captures the mundane boredom of a 9-5 office job. Many of the drones work in single cubicles, which is a office plan that is slowing dying out as, I think, as more companies are going for a open space office plan (or at least I think they are). Endlessly quotable and still relevant - in fact it even invented a heavily used meme.
Another film that depicts an office environment in a comedic way is 9 to 5 which is perhaps more interesting when it's looking at sexism in the work place in the 1980s.
Absolutely rude and endlessly quotable, Glengarry Glen Ross is based on a stage play and depicts the behind the scenes action of a real estate office. Lots of swearing, lots of angry men and the some of the best actors of the 90s (and Alec Baldwin) deliver superb performances.