Scottish independence.
I live in Scotland but I'm English, with a very distinctive regional accent, so anyone that crosses my path is immediately aware of it, despite having lived here for almost an equal amount of time as I have lived in England, now.
I've never raised the Scottish independence topic in my life, but have had a fair few Scottish folk raise it with me, then become quite cross and at times nasty, when they've harangued me for my opinion, which simply is, I don't think it'll be quite the sunshine & lollipops folk think it'll be. Also that many parts of England, particularly in the North have a bloody rough time of it and similar experience to Scottish folk with feeling like Westminster isn't for them, and that I don't agree with the voting of SNP because I don't agree voting for any nationalist party that has fuck all interest in the rest of United Kingdom - precisely because like it or lump it, we are united until indyref is successful. I get their point about seats in Westminster, but I will always vehemently disagree with national parties in the UK, until they are independent. For that reason, I actually wish Scotland would leave - so they could all shut the fuck up about it. They'd still blame England when it went to shit, though.
I've been on the receiving end of a fair bit of resentment and snide comments from Scottish people in the name of 'banter' over the years, if you can't tell. At work, from neighbours, 'friends', acquaintances, all in the name of a joke. I'm fucking tired of it. Despite the fact I love Scotland and it is otherwise very welcoming to foreigners, unless you're English. I'll never feel at home as a result.
So yeah. I try not to talk about the fact I'm English, as much as possible. Add that to the list.