The comments are awesome on this. :) I reminded of the time I visited the north of England and my grandmother's village. The B&B hostess invited over an elderly gentleman whose brother had attended school in the village when my great grandfather was the schoolmaster. It was wonderful to meet him, but I really, really struggled to understand him. I did get a few of the tales, but I know I missed out on a lot, as it was a dialect more than an accent. The one thing I do remember him saying was, "We had scholars in the village when your grandfather was the schoolmaster!" Alright, so he confused grandfather and great grandfather! :)
Surprised people had problems with that. Perfectly understandable to me.
I was in Glasgow during the TRNSMT rock festival in 2017 and a young man who was absolutely plastered tried to strike up a conversation with us on a bus. I could’nt understand a word of what he was trying to say (except the F-word, he used that a lot). I think he was just trying to make friends, he seemee to be really frustrated that we didnt understand him.
There is a language course available. Try this free sample: https://youtu.be/T_Lk7qivXbw
Legend has it that when Graeme Souness (born Edinburgh) signed for Liverpool, he couldn’t understand Kenny Dalglish (born Glasgow).