It's hard to believe but an entire decade has passed since we were last given a glimpse inside the walls of Wernham Hogg. He may have popped his head around the corner for Comic Relief but now, making a special appearance for YouTube's Comedy Week, our favourite ''chilled-out entertainer'' is back. And 'Learn Guitar with David Brent' is every bit as brilliant as it sounds. The Office leapt out of a dreary Monday evening and changed the face of situation comedy. It was almost as if the secret formula for sitcoms had been discovered hiding under a Slough trading estate. Before its arrival in 2001, your typical sitcom was circus of stock phrases and studio audiences. Now, it's almost impossible to find a script that has resisted its influence. It has won countless awards, been remade across the world and not only propelled its creators, Ricky Gervais and Stephen Merchant, to fame and fortune but also made actors Martin Freeman and Mackenzie Crook into household names. It told a story both hilarious and heartbreaking. It reflected a world familiar to millions and yet offered something completely unique. It combined the white-collar ennui of the modern workplace with a self-conscious, Sartrean swipe at the human condition. It also featured a man doing a silly dance. Here (in no rank order) is why it deserves the comedy crown...