Comment by SyneRyder

That's strange to me that you mention London as being similar to Glasgow. I've not had the chance to visit either, but my go-to on this topic has always been this faux news story on the Mash Report:

Northener Terrifies Londoners By Saying "Hello"

https://www.youtube.com/watch?v=1YxLiLFjYKc

I hadn't noticed it before, but they even specifically mention the use of headphones as a defense mechanism near the end.