David Attenborough is the first for me. I definitely agree on Stephen Fry. Pretty much the BBC English. Concerning American English, George Carlin of course. And that man Hugh Laurie. Wait...what? :p
The second thing is the dissapointment you feel when you actually visit the countries and hear the natives speaking.
The third thing is Brits trying to correct your 'American' accent, while Americans constantly asking why you have a British accent.
The reality is you don't have any of those accents, or any accents and you just go on buthcering the language in every department trying hard to express yourself, esp. when drunk as people often are on vacations.