You are probably already familiar with the ideas of cognates and false friends. Cognates are words which are related to each other in different languages. English and Romanian, for example, contain a fair few cognates, since Romanian is Latin based, and English has tons of Latin based stuff in it. English and Hungarian on the other hand have very very few cognates, because Hungarian is just bloody weird. (And because they have one of those academies which insists on creating new words for new things, they don't even have easy-to-grasp words for things like "The Internet" or what have you).
False friends, are words which you think are probably cognates, but turn out not to be. The most famous example of this is the Spanish word embarazada, which means pregnant (and not embarrassed as people tend to assume). Though my personal favourite is the Portuguese word constipação which actually means "a cold", and so (because I have a puerile mind) makes me imagine Portuguese tourists going to the chemists in the UK while on holiday and asking for medicine for their cold, and getting something else.
Hungarian to English has one or two false friends - trafik, for example, actually means kiosk or tobacconists (there must be a "My hovercraft is full of eels" joke I could squeeze in here, but I can't work out how). Akció, on the other hand, means "special offer" or "discount", and not anything like "action". (This is also a Hungarian/Romanian false friend, as you sometimes see shops here with signs in the window saying Akció/Acţiune, which makes the same error. A slightly ruder example is the Hungarian word Szakadék which means cliff or abyss, and nothing like how it sounds (which is more or less "suck-a-dick")
Between English and Romanian there are one or two which come up all the time - nervous being the most obvious. The Romanian word nervos actually means angry, and this causes people (not least me) a lot of confusion. I think the Romanian word mizerabil means something like filthy, which is also a tad confusing. Then of course there's the common menu item crap (fillet of crap, fried crap, grilled crap, etc).
But, I have come upon a new concept here, and that is the cultural false friend. There is a Romanian word imediat, which you hear very often. How long will it be? Imediat. When will you be finished? Imediat. When can I expect it? Imediat. Now, in theory, imediat is a cognate. It means, as you might expect, "immediately". It's just that in English, immediately means "right away", or "I'll drop everything and get it done right now". It doesn't really mean that in Romanian. It means something more like "soon-ish" or "when I get round to it", or "in a week or so". So, I've had to mentally redesignate it as a false friend, or otherwise it just gets too confusing, and more that that, it creates unreasonable expectations (for me).
Any other cultural false friends? Or even just amusing linguistic ones?