Most people argue that the first season of the Americanized Office was too similar to the British original (and it certainly applies to the pilot episode, which was co-written by Ricky Gervais, Stephen Merchant and US developer Greg Daniels), most notably in the number of episodes in the first season: just six, like a standard UK sitcom. However, the reduced episode order was probably due to simple caution on the part of NBC, who wanted to check if American audiences would respond to the series before requesting a standard-length season.
Funny coincidences aside, Hot Girl is a very amusing season finale, in which most of the male staff go "crazy" when an attractive saleswoman (Amy Adams) shows up in the Dunder Mifflin building. Michael and Dwight make fools of themselves immediately, Roy makes an inappropriate comment in Pam's presence and Jim... well, he doesn't have any problems, really.
While not exactly setting up a second season, Hot Girl works admirably as a finale, reminding us why The Office is such a terrific show with some priceless displays of awkward comedy (anything Dwight says) and pure laughs (Ryan washing Michael's car: genius). A frustratingly short first year, no doubt, but with hindsight a juicy appetizer for what came next: one of the greatest comedy shows on television.