I can answer that for my personal wants/needs:
1. It's where my best friend lives, and I miss being with her.
2. She has a puppy, that I bonded with for two months before I left, a Sprocker, and I miss that furball with my entire being.
3. My best friend and I do want to get married someday, so its more than just about "oh I miss my friend" (she has said yes to marrying me, just fyi, we just can't afford the lawyer just yet to help us with all the paperwork) ( I am currently saving most of my money with the hope of going back more prepared someday)
4. As someone who couldn't afford medicine at the age of 17 when I had salmonella poisoning, and threw up for 3-4 weeks crying myself to sleep every night wondering if I had a misdiagnosis and was dying of cancer (I lost a lot of weight during this period in my life, and couldn't eat anything) I really want to live in a country with Universal Healthcare and medicine that goes based off your income or the 9 quid a month rate England uses, personally I think 9 quid is too low for a 30 day supply, they need to raise it to 15 quid a month for a 30 day supply and give nurses a big raise from that
5. My partner and I would go walking every day, because the cities and towns are much more walkable there, in America I never seem to walk even though I always tell myself I will... its just designed for cars here... my fault for not pushing myself, but I don't have to push myself in England, it just happens naturally I lose weight every time I go there, in a healthy way
6. part of me doesn't even want to own a car anymore just because so much theft is occurring, like with catalytic converters, in England my partner and I only needed public transport to enjoy ourselves, so that high cost of owning a car is null, risks associated with owning a car null, general anxiety from how expensive cars and petrol are in general are null, and public transport in her small town was great, public transport in small town America doesn't exist, and I don't want to live in big cities
7. My ancestry dates back to the 14th century in the Shropshire region, and I have to say every time I there I do feel something spiritual about it, it feels like home for me, my body just relaxes, I can't explain it.
8. Crime in general in America is becoming worse, people are becoming nuts here, largely because of morality no longer has a reason to exist, it is the Categorical Imperatives by Immanuel Kant come full circle sadly... (no one is a role model anymore)
9. Shootings happen daily here, its wild to me that I live close to a warzone (Chicago) which has a higher death ratio than the middle east wars... that just doesn't happen in England, you will get some nut jobs in England from time to time sure, but nothing on this level, not even close.
Source Statistics
10. If my partner and I decide to raise a child, we want our child to have access to affordable University and healthcare
11. I prefer and feel safer at the beaches in the UK.
12. There is a special forest my fiance and I love walking in England, its just our special place, and it can't be replaced with any other forest. Thankfully its a National Trust area, so we don't have to worry about it ever being destroyed.
13. Sainsbury's has the best fucking food I have ever had in my life, seriously the grocery stores where I live suck ass in comparison (probably is better in the big cities, but again I like that I would have access to all these amazing foods just from a store down the road in a small town) I hate traffic, and prefer to avoid big cities in general.
14. Fuck I miss Sainsbury's…
15. Did I mention how much I love the food at Sainsburys yet?
16. No mosquitoes. FML I can't enjoy summers here, mosquitoes in middle of June through late August are just horrible... I seriously can't be outside for even 5 minutes without getting bit, and England I had 0 issues with bugs there... it was heaven. Finally able to enjoy the hot weather without chemicals on my body (mosquito repellent, which I despise wearing, its nasty)
17. Fuck I miss proper chicken tikka masala and buttered chicken, there is a place near me that has this, but its horrible in quality compared to what I had in England.
18. People are nicer to me in England. I made friends with quite a few strangers in small town England, my favorite being this old guy who owned and ice cream shop, he got to know my favorite scoop and would joke around with me and such. In America people are very "robotic business" personalities, 'thank you and have a nice day', and no actual conversation. (Maybe my accent is the only reason its different in England? I am unsure)
19. I can ferry boat over to Ireland and France and experience entirely different cultures cheaply, well insert RyanAir here as well if you are willing to travel with no carry on and no bag... (which I am) its amazing to me you can fly for like 20-30 Euro to Paris for a weekend and stay at a AirBnB and then next weekend 60 Euro to Turkey and see the beautiful architecture. (these flight prices simply don't exist in America, if I want to go to Colorado and see the mountains, it will be 400-500 round trip flight, not to mention air bnb's are a little more pricey here.
20. You have clean water. We use bottled where I live (and no I don’t live in Flint Michigan) most of America has old lead pipes and/or just bad quality water. I measured 450 parts per million in my houses tap water… so now I drink bottled premium water only (no soda, no anything else).
21. You don’t really have winter. I hate winter, back of my hands crack and bleed, my eyes get super dry and vision blurred, lips chapped. My fiance says England gets winter, but I looked at the temps and laughed… no you don’t get winter. That’s still shorts weather for me, maybe two weeks total you get winter, but not a full proper winter, at least not the part of England she lives in, I am sure Scotland where you are is worse, but I won’t be in Scotland.
22. Open Top buses to beaches. It was so awesome being able to walk down the road, get on an open top bus during the summer time and go to a beach any day of the week cheaply (8 quid return)… just can’t do that in vast vast majority of America, in fact, America may not even have a single city that offers this, at least to my knowledge.
23. ---28 days of vacation time at almost any job for anyone in the UK, is such an insane benefit you all have no idea how lucky you are. I worked as a Security Guard making almost minimum wage for a few years, and only had 1 week of vacation. Would have taken 15 years working for that company to get 28 days vacation per their policy (many companies I have worked at are like this). You all get it on day 1. Another example, my Dad is 70 years old, still works 50-60 hour weeks, hasn’t had a day off in over 5 years other than when he had surgery. His company gives him two weeks vacation now and has worked at this company for close to eight years (FYI he was unable to take his vacation in recent years due to staff shortages so they just send him an extra check for the vacation...). Why would I want to live in America with this quality of life to look forward to? My fiance on the other hand, was going on 3-4 weekend vacations with me almost every other week during my stay last year... it was a blast and our quality of life was night and day different than back home in America.
24. I laughed daily when I lived with my fiance. I have laughed maybe 5 days total out of the last 80 or so being home in America.
25. Driving all the roundabouts on the rare occasion we did rent a car I found to be quite fun, also the country roads being one lane a lot of time, and everyone being kind backing up, or you back up so they can pass... you just won't ever get that kind of hospitality in America, you will get someone roaring down a single lane with the attitude of get the **** out of my way or get run over... I never experienced any hostile drivers in England, in America they are a dime a dozen though.
Lastly, you referred in your post to knowing people that have moved there. I am open to any advice on how to make it happen for myself or get a work visa sponsorship, please let me know how. In fact, I will get on my hands and knees and beg you for advice if you know any.
Cornwall or the Lake District aren't too shabby, either. If I and the missus had jobs waiting for us, I'd move to any of these places without a second thought.
Craft beers on the other hand... mmm! 
I would love to try biscuits and gravy one day, though.
