My wife and I recently spent a few weeks in Ireland, including three days in Dublin. In those three days we took three cab rides: one each from and to the airport (to pick up a car) and one because we had taken the bus to a distant sight and were tired and didn't want to deal with figuring out another bus route for the return.
All three cabbies were amazing. It was as if we had hired a tour guide who happened to drive a car around delivering passengers. They were exceedingly friendly, extremely knowledgable about their city, and more than willing to offer commentary about historical sites we were passing as well as restaurant and bar recommendations, all while cracking wise in a good-natured manner.
It was incredible. Now, don't get me wrong. I've had some enjoyable cab rides in the U.S.. In particular I remember one with Afghani airline mechanic in the Los Angeles area who was amazingly friendly but very much wanted to find work in his profession. Even with that experience, these guys in Dublin were amazing.
Based on my (admittedly limited) experience, I hereby would like to propose a compliment for the English language:
Friendlier than a Dublin cabbie.
In my experience, that would really say something.