A lot of hard work has gone into that Joe .
Please believe - it's not repetitive - he has the framework intro for each song, but the humour varies - mostly because he tries to make it different for people who he is concious are seeing him for the "nth" time - and just as important- he stretches himself - to see if he can make himself laugh.
As you probably know, he's a complete "One Off", he gets the sense of humour from his Dad - who unfortunately has now passed away - but Alf could equally be described as a "One Off" also.