It’s absolutely true that the image you receive of another country necessarily belies the reality. It’s impossible to truly understand what it means to be or live somewhere without experiencing it yourself. I’d like to go the US one day just to see how much of what I imagine to be true stands up to the reality !
Britain certainly has its problems and inequalities, but universal healthcare that is free-at-the-point-of-need is a remarkable and rare thing (although some would say that is also being gradually eroded now). The NHS is by no means perfect, and I don’t think the quality of healthcare is as good as it is elsewhere, perhaps, on account of the enormous demand on its resources. But the fact that you always have that safety net to support you when you need it is invaluable.
Your final question is a good one. Perhaps what our experiences and opinions show is that nowhere is really as good in reality as it might seem in films, in books, on the news, etc. Being very idealistic, I suppose the best thing would be if we could reform our societies to valorise those positives and work to reduce the negatives.