What makes St Paddy's day worthy of celebration is that the Irish have a reputation for being friendly and knowing how to have a good time.
As an Englishman, I have to say that we aren't quite as carefree about celebrating our national day as the scots, welsh, irish etc.
BTW, a few years back our local council granted the bars an extension to opening times on St Paddy's day. An application to do the same on ST George's was rejected on the same grounds!