I thought the “it’s grim up north” phrase referred to the NW .... the industry, smog, and the cold weather a la Lowry. Did it refer to the NE as well? How far north is “up north” and therefore “grim”? 
Everything North of the Wash,
though Londoners often move it to the Watford Gap!!!!! 
.... so, much of the country then ... 
North of "up north" is Cumbria, Scotland and many, many "ungrim" places.
There are certainly grim and ungrim places all over the country Viktoria, and even many of those "grim" places have their charms. It's all subjective anyway isn't it. 
Yes indeed ,in many cases it is what / where you grew up .
In Manchester we lived very near the gas works ,industry and mills ,row on row of terraced houses,the awful back to backs had gone years before.
Coming back to that from rural Shropshire was a shock ,I was well cared for I Shropshire and quite happily have stayed ,but the war ended and so I went “.home”.
But I adjusted, made friends and was treated well by those new friends, my funny accent used to make them laugh in a nice way,that is when being comical,first
came to me, I always had friends because I could make them laugh.
Also the people with whom I was evacuated were so kind and such good examples.I wasn’t selfish etc,Was the peacemaker in others’ quarrels.
I feel privileged to have had both ,you see I suffer from inverted snobbery,
I like it that I came from a working class poorer area,only sorry it was not the “pits” of Manchester slums !That would be something to tell the grandchildren.
You know, where you could get mugged by nuns and the Police dogs would only go in threes!
Seriously, the people were a mixed bunch but nice little spic and span houses,clean kids, people getting on through sheer hard work and education.
I am proud of being part of that.
The history of Manchester in particular and The North in general is fascinating.
People make history , and I am in there somewhere ,not named but by just living there.
I am off now to step stone the step and flags ,polish the door knocker after having shaken the door mat by banging it on the wall,woe betide anyone who stands on the flags or step,I am not a Northern housewife for nothing .
So think on!
Viktoria.