As we saw soon after in Knocked Up and much more recently in Bridesmaids, anything that has Apatow's name on it is a masterclass on giving good actors free reign to be real people. The nuances of unscripted human communication, the tics particular to a certain character, the concerns that occupy the thoughts of people of a certain age – they're all given room to shine through very clever scripts and very talented and funny people.

In lesser hands, any movie poking fun at a meek, nondescript guy like Andy (Carell in his breakout role) who's managed not to get laid by the age of 40 would be obtuse, obvious, cheap, telegraphed from a mile off and not nearly as funny. But in further proof that we care more about characters than we do 3D, effects or violence, Apatow's script gives Andy and his many friends and colleagues so much depth while still managing to be one of the funniest films ever. Andy is neither stupid nor pathetic, and Carell doesn't play him as an over the top caricature like he did the far less interesting character in Dinner For Schmucks.

The plot is deceptively simple. When Andy is outed as a virgin despite his advanced maturity, the manboys he works with at a technology store try various methods of helping him pop his cherry, all of them dealing with their own issues and dynamics. But Andy's salvation might come in the form of the cute but slightly ditzy Trish (Kenner) who runs the store over the street.

The fact that Trish isn't a drop-dead gorgeous model is another tick in the film's favour, but where other movies would coast on such an accomplishment, Kenner gives Trish as much reality and humanity as Rogen, Malco, Rudd and everyone else. It's a classic not just of comedy but of scripting and improv too.