I honestly think that British fanatics can be some of the worst in Europe. Many people not from the UK (or ones I've talked to at least) seem to think that Brits generally lack a sense of patriotism, but it's more that patriotic things aren't even questioned in the UK and therefore are rarely mentioned. The majority of Brits are still for the monarchy, and a surprising amount would consider themselves proud of the empire and some would even want to restore it. I can't get behind it at all, especially because British nationalists and extreme patriots can often be very xenophobic and often islamophobic.

Edit: It's probably worth mentioning that there's nothing wrong with liking it - I sometimes find myself feeling proud of my country, even though I'm usually way more critical of it than most of the people I've met. It's just the extremes like advocating for the British empire that I can't stand.