Acting more Australian to foreigners for a laugh only to realise I'm being less Australian than I would be with other Australians.
Sometimes I try to play up the Australian accent/stereotype to foreigners for a bit of a laugh, only to then get in to a conversation with other Australians and realise I was actually playing it down.
I was chatting with a yank fella I know on Discord and called him mate, I've known him for about a year. There was a pause and he said, "That's the first time you've ever called me mate". Bloke was just about tearing up cos apparently I'd just fulfilled one of his life ambitions, being called mate by an Aussie. Ordinarily I use mate just about every other sentence but it made me realise I must subconsciously tone it down for foreigners.
For me it's sentence structure and grammar. I'll use words like 'mate' when talking to non-aussies but they'll be in very formal sentences. With other Australians all that gets chucked out.