The night Joe Dolan's car broke down

Went to see the above-titled play at the Olympia last night. God, I haven't been in the Olympia since I saw John Otway there some time in the early nineties. The rows of seats are so close together its impossible to stand up and let people through. Everybody has to leave the row then file in after the latecomers!
I have to say I enjoyed the play - very unusual, almost a vehicle for a Joe Dolan tribute band - but plenty of comedy in there too. There were weaknesses too - the means by which the obligatory guilty secrets of the cast were revealed was very cliched. The secrets themselves were pretty unoriginal too and frankly a bit unbelievable.
But the guy playing Joe himself was terrific and also the character of The Horse, a type everyone can readily identify (says he, not trying to spoil any of the plot)
There's a lot of laughs in this and I was trying to analyse the source of the humour. There seem to be two main subjects of humour - 1) rural Irish people being drunk and 2) bad language. With regard to the latter, I was yet again mystified by how "Go away, y'eejit" is not funny, whereas "Will ya ever fuck off?" is greeted by howls of laughter.
But I don't want to give the impression that the play isn't funny. It is. Go see.