Paul did indeed make an error at the end, and the other three Beatles liked it enough that the kept it in. The phrase Ob-la-di Ob-la-da means "life goes on". Also, Paul actually heard the phrase from a Nigerian congo player in a group called Bad Manners named Jimmy Anonmuogharan Scott Emuakpor. Jimmy actually tried to sue him for using that phrase, a lot of events followed, and Jimmy dropped the case after Paul payed the support money that Jimmy owed his ex-wife and they both became close friends afterward.
Paul did indeed make an error at the end, and the other three Beatles liked it enough that the kept it in. The phrase Ob-la-di Ob-la-da means "life goes on". Also, Paul actually heard the phrase from a Nigerian congo player in a group called Bad Manners named Jimmy Anonmuogharan Scott Emuakpor. Jimmy actually tried to sue him for using that phrase, a lot of events followed, and Jimmy dropped the case after Paul payed the support money that Jimmy owed his ex-wife and they both became close friends afterward.