Being British is an accident, not an achievement but I don't like to see the UK being run down, nor made to appear ridiculous: looking at you Boris Johnson.
I no longer have a vote in the UK, which pisses me off as I pay UK taxes, but am still keenly interested in what goes on. All but one member of my family lives in the UK.
As a dual citizen of the UK and Australia, I still feel British, unsurprising as I lived more than 50 years there before emigrating. Cricket? yes, always support England in the Ashes, and I don't even like cricket. I feel gratitude to Australia that I'm a citizen, and can't be doing with the lazy, xenophobic shite that pours out on some MN threads, so will always take it on. By contrast, I stay off threads about the UK being down the toilet as I feel my long absence means I mostly don't have anything relevant to say, though I read them - family, innit? 
I think what has helped was not coming to Australia because we thought the UK was a pit or the weather was better in Oz, but had an opportunity not to be missed. No rancour or dislike of the UK, still love it, and no unrealistic expectations of Australia, and love it too (eventually) 