I guess when you choose to leave the country you grew up in, it's because there are things about it you don't like. You're often asked why you moved to the country you end up in and “do you like it here?” so you're commonly called to think about what you didn't like about your country of birth and what you like about the country you're in. It's been a while since I was asked to talk about anything I love about the country I grew up in, if I ever was.
While England is most definitely not known for its good weather, it does have other things going for it and those are the things I miss. Probably the main thing I love about the UK is the physical history and old buildings. In Australia, we have old buildings, but they aren't more than a few generations old. We also have a certain amount of aboriginal artefacts, but not many, because much of what they used was natural and has long since returned to the earth.
What the UK, and indeed most of Europe has, is physical evidence of history which can go back not just hundreds of years, but thousands and we often lived amongst it without always being fully aware of it. Not long before we moved out to Australia, I took a short holiday with my sister to Ripon in Yorkshire. One of the places we visited more than once was the cathedral and the main fascination it held for me was the sheer age of it.
While the building which stands there today, which was built between the 13th and 16th centuries, can only be said to be hundreds of years old, it is unique in that there is a crypt within which was built in 672, which you can still set foot in today. That's well over a thousand years old! Is not a roomy stairway which leads down there and it's probably only comfortably accessable for children and petite people, by modern dimensions. Some people today may even physically not be able to access it, indicating how much smaller people must have been back then.
More local to where I lived we had the town of Bath and Matlock Bath, named for the Roman bath houses built there during the time of the Roman Empire and occupation. I believe some of the baths in England are kept functional to this day, for tourism purposes more than anything. I would have loved to have actually been able to try a functioning one, but never got the opportunity. These would date back to between around 43 and 410 AD, yet they are still not the oldest structures in the UK.
The oldest building remains seem to be mostly in Scotland, with the Knap of Howar looking to come in as the most ancient at between 3700 and 3500 BC. That's well over 5000 years old; older even than the earliest pyramid in Egypt!
I also love the greenness of Britain, despite the fact that I know those green fields would be accompanied by the mud from the almost continual rainfall. When I picture England it's often with the old cottages surrounded by the lush green, or the trees of the Peak and Lake Districts, where I've had many a stroll and hike.

There is just something humbling about seeing the work of people long gone, which has survived the ravages of time.
This is in response to the Hive Cross Culture question, what's something you love about the country you grew up in?