I remember the first time I went into a pub and ordered a Guinness. This was a good, proper pub that poured it on nitro, had the glasses, and knew what they were doing with it. I'd had Guinness by the can and bottle before but there's something special about getting a beer on draft. I also remember going into a pub a few years ago and ordering a Guinness and noticed an extra step in its serving, drawing a shamrock in the foam. I thought this was a cute little touch at first, but the more feedback I hear from people whose opinion I respect in such matters, the more I dislike the idea.
The original piece of negative feedback I heard on the subject was from a character named Super Hans on the David Mitchell show, Peep Show. He said you were effectively drinking an advertisement for a product you're already drinking. I find that argument a bit lacking, but it is a point. I more prefer the argument that it actually diminishes the ritual of the perfect Pint.
As a friend put it once, "Never go into a bar that has a neon shamrock." The Shamrock in the pint seems to be the mark of a place that is Irish for the sake of being a theme restaurant. There's a big difference between your chains and your properly Irish pubs. A pub is simple, it doesn't need frills or flashy lights. It just needs good beer and quaint surroundings to be with friends. I can't stand plastic cups. Karaoke belongs in karaoke bars. Irish Pubs just need beer, proper beer. It's a pub, not a Starbucks. I've said enough quotes this post so I think I'll close on a song that explains what way too many pubs have become: