Cultural insights are one thing but the issue is if you slip into full flow of Britishisms and let your accent loose people who only speak English as a second language can't understand what you're saying.

There's nothing unique about this though, it's the same for every language - it's one thing knowing Spanish well enough to hold a conversation where the other person is speaking slowly and making it easy for you, it's quite another to be able to slot into a group of native Chilean Spanish speakers in full flow.

I travel a lot so I'm used to adapting my use of English depending on who I'm talking to. I find there's a way to express things and still enjoy using the language without making it hard for non-native speakers to understand. But also, when you do end up in a group of entirely Brits it is fun to be able to just let loose