This probably won't wash with purists who like to think of Billy the Bard as unassailably perched atop his pedestal, but it seems that some of the crappiest lines might have been written while he was hung over! Dominic Dromgoole, artistic director of the Globe reckons that there are "Monday morning lines" in Shakespeare's masterpieces.
So which lines were probably written under the influence? John Sutherland has a whole list of candidates in the Guardian.
More discussion of Shakespeare the Boozer on Michael Prescott's blog.
And I love this poem pete the parrot and shakespeare by humourist DonMarquis which depicts our Bill sobbing on Ben Johnson's shoulder down at the Mermaid Tavern, lamenting about how all he wants is to be a poet when he has to keep churning out plays. There could be some truth in it.