Love G&S. Reading this thread makes me realise how many of the best comedy moments in it are related to music - part of its genius, I think.
Whenever we order a curry, there's a good chance that someone in our house will either say "Will people think I'm boring if I have a korma?" or launch into Smithy's "Chicken bhuna, lamb bhuna, prawn bhuna, mushroom rice, bag of chips..."
The thing that has always amazed me is how Ruth Jones and James Corden managed to produce something so funny and so original when neither of them had written anything before. Corden, I think, was only in his early 20s. How did they do it?
Typically, most successful sitcoms (Porridge, Fawlty Towers, Father Ted) start from the premise of having a group of people trapped together, and the comedy comes from the friction between them. Domestic comedy on the whole tends to be very anodyne (Terry and June, My Family etc).
But in G&S people aren't trapped, and for the most part they all like each other. Such a hard thing to pull off. I think a lot of the joy is in the attention to detail in the creation of each character - the way, for example, that Smithy doesn't just call Pam "Pamelah" but calls Gavin "Gave-lah" and so on. Just wonderful.