Poet’s Day Cockney Rhyming Slang
Poet’s Day is Cockney rhyming slang for friday
Because Friday is known to be a day in the working week when one can “Piss Off Early Today”, so Friday has become known in the world of work as “Poet’s Day”.

Because Friday is known to be a day in the working week when one can “Piss Off Early Today”, so Friday has become known in the world of work as “Poet’s Day”.