However, my vocabulary is a weird mix of British and American terms as I picked up a lot of words from American films and TV and books. Of course, I also watch and read a lot of British stuff. English in my head is a sort of jumble of terms from both and sometimes I know which belongs where but sometimes I don't. Now that I live in US it makes me confused sometimes. For example my 'tap' was leaking. So went to asked for it to be fixed and get empty stares when I said my tap was leaking. It took me explaining what it does to get the 'faucet' fixed. I didn't understand as I heard Americans say tap water before. I was sure 'tap' was an American.
I get called on the Briticism I use from time to time. I say 'lift' or 'pavement' and don't even realise it. I know Americans drop something from 'aluminium' but I can't remember which and I end up saying 'alumium?' or 'alumnium?' and it's bad so I stopped trying (it doesn't help that it is 'aluminium' in Polish too).
I though I was used to it and kind of keeping it under control after two years (except for 'aluminium', it's too tricky). So when I started to see the articles about Briticism popping up everywhere I was surprised to learn how many words I though to be part of standard English everywhere are actually British English. 'Brilliant' 'ginger' 'holiday'. I certainly am guilty of saying 'flat' (still am not sure what to replace 'block of flats' with when I explain where my family lives). I personally hope this trend continues so I can mix the terms and be understood. I'm too lazy.