(Non-native English speaker here.) I worked for a Scot in Dublin for three months before I realized his accent wasn't Irish. I also had almost no problem understanding him.
On the other hand, I find it almost impossible to read text that is supposed to show Scottish accent, like the one from arethuza.
Listening to that phrase would be worse in reality as folk from the North East of Scotland tend to talk quite quickly and without proper breaks between words.
I've probably said something like that many times when I was younger (I now have, as someone described it, an "affected Edinburgh accent"). However, you can get silly Scots phrases like:
"Fit fit fits fit fit?"
Or, my favourite:
"Aye, ane an an ingin ane an a"
The latter I can't say without almost singing (and smiling).
On the other hand, I find it almost impossible to read text that is supposed to show Scottish accent, like the one from arethuza.