The reasons for this will become clear as his act progresses. Except we never actually get to the act. Every time he's about to deliver his routine, he gets sidetracked by the uncontrollable urge to share his domestic issues - his in-laws have just moved into his two-up-two-down home in Exeter, and his mother-in-law is driving him demented.
Wozniak doesn't exactly parody 1970s working-men's club comedians, nor does he look back on them with anything like nostalgia. Instead this is a clever portrait of a man on the verge of a nervous breakdown. Over the course of an hour, Wozniak has to prove his chops as an actor as well as a stand-up; and he does, becoming a more dishevelled figure as the minutes tick by.
There are routines to laugh at along the way - police horses, graveside monologues and the weight of Michael Fassbender's, uhm, not-so-hidden other talent - but we don't come away with a one-liner or set-piece chunk imprinted on our minds. Instead it's the accumulation of detail, the escalation of the character build-up that is impressive.
By the end, I might not have wanted to hear his "showbiz" act anyway, but I would've been happy to keep him here a bit longer to save him from returning to the home front.