If you type 'accents into the 'search' box you will see this has been asked many times before. I'm not saying it shouldn't be discussed again but I just thought you might like to see the previous opinions:
My husband is welsh, but barely has an accent. I'm not keen on the welsh accent - they say pronounce boat like "boart" and no "naw". Also, when my in-laws talk to my daughter, they say "Shall we go to the park then, is it?" They say "is it" at the end of everything and it doesn't make sense!
I'm not keen on Nadine Coyle's irish accent at all. I'm not saying my ultimate 'worst accent' but it's known as the one that makes you sound dumb lol.