I was born and brought up in Toxteth, Liverpool which I'm proud of but my father got a good job at Michelin in Burnley when I was a kid so we had to move there so accents and dialect became a big thing with me. If I spoke my normal accent, no one could understand me so I had to modify it and still do so depending on the company I'm in. One phrase from east Lancashire though that to me defines the speaker as a real thicko is 'anaweragert', or, to break it down, "anne a-(sharp a) wuh ra gert" which means roughly "So I said to him/her" or, 'so my attitude to this situation was". They seem proud of using that phrase and do so throughout their normal conversation.
I am pretty good at understanding any English-speaking dialect except one - Doric. I used to go to Aberdeen quite a lot on business and was once sitting waiting for my appointment and heard two people speaking. I assumed they were conversing in Gaelic because I couldn't understand it but I heard the odd word I did fully understand and came to realise this was the legendary Doric. Even my Scottish colleagues of the time admitted they were lost on that particular accent.