Yes, your impressions are utterly rose-tinted OP and that's why people love to go on holiday - they get to step outside their boring, humdrum lives and live a life of leisure and pleasure for a week or two.
As for your comparisons - Canada? Most of Canada is bitterly cold for about six months of the year and the bit that isn't (i.e. the west coast), is grey and rainy. It's boiling hot in summer (the bit that's bitterly cold in winter), and they have masses of bugs, many of which bite. The west coast bit is admittedly lovely, but then the UK is often lovely in summer too.
Spain - I agree that the climate in much of Spain is lovely, particularly the coastal east and south coast areas - which is why they've become so built up and full of holidaying people from cold, dark, northern Europe. The middle of Spain is quite cold in winter though and is roasting in summer - not so nice and not so easy to work in either - which is why they have a siesta. It's not because they like to laze around in the middle of the day, it's because it's so punishingly hot that anything except lying in a darkened room is unbearable.
As for Italy - it has a lot of problems. Many young people can't get jobs, earn very little, still live at home with their parents until their mid or late 30s, there is hideous bureaucracy, nepotism, corruption - it's not an easy place to live and get on. There is very little by way of meritocracy in Italy and I wouldn't want to live there, however lovely the pasta and the wine is.
In other words, if you live a damp, dreary part of the UK, move or make the best of it, but the grass is often dry and brown elsewhere or frozen solid for months.