I'm an European immigrant living in Wales and relocating to Scotland next year. Lived in England for a few years before that too (Midlands).
Let's get one thing out of the way: the weather is shit. That's a fact, unfortunately. Personally, I love mild temperatures, I'm from a Northern country with -25 winters, so it's never cold for me in the UK and always 'mild'. But the rain is shit.
However. Boring? Absolutely not. It has something for everyone, I'd say. I'm not a countryside/nature person at all (that does bore me to tears, sorry) and my own home country has plenty of that. But for 'nature' people UK has a lot to offer, as proven by lots of replies.
I love cities, people-watching, history, culture, architecture, museums, traipsing around and getting lost in little streets, music, gigs, cinemas, etc. UK is great for all of that, far better than my home country. I definitely don't find it boring at all.
Yep, shops are a bit samey, but I don't like 'browsing' and shop online, so that's irrelevant to me. I do like flea-markets and I wish there would be more of those where I live, though.
As for people.. Rude??? Who? English people? Scots? Welsh? Hahaha.. That's probably the funniest thing in the OP. Yep, the people are reserved, but I found most of the Brits to be very very polite, well-mannered, kind-natured, helpful and friendly on the whole. Don't want to diss my home country, but Brits are just on the other level of politeness. Yep, you can meet rude assholes sometimes, but you can meet them all over the world, of various nationalities.
That said, I'm an introvert, so Brit-reservedness suits me to a T. I couldn't live in Southern Europe. No disrespect, I find Italians/Spaniards/Greeks friendly, lively and helpful, but I just can't cope with that level of emotion for longer periods than weekly/bi-weekly holidays. Just how I'm wired.
So now, I really don't find UK boring, not at all.