United Kingdom

lol true. I am a Protestant in Northern Ireland, but even then I had to resort to getting an Irish passport to visit my girlfriend in China, as the Irish Passport has 30 day visa-free entry, and was cheaper to get one than a visa on my British one.

However, just say I wanted to cross into Vietnam, I'd need to present my British passport as it's the other way around.

From what I hear, the British passport is better for long-term stays in some places. You get 180 days in Hong Kong SAR vs the Irish passport's 90 days. And if you're migrating to or having a long-term stay in Australia, it's more straightforward with a British passport.

Some reckon that the consular assistance is better with a British passport (People in Northern Ireland typically used this to justify a British passport which was slightly more expensive), but I don't know if that's the case post brexit. I remember the crisis in Sudan a number of years ago, the Brits were still stuck there while the Irish had already been evacuated by the Germans on account of the EU. I believe every EU diplomatic mission is actually supposed to support EU citizens regardless of nationality, although possibly in cases where their home country's mission is inaccessible. Still would be nice, for example, a German citizen staying in Belfast could seek help from the Polish consulate if needs be.