A friend of mine from Norway was studying with me in Lancaster, England. We were getting ready to go out, and she was wearing a rather short dress (but being the tall, willowy thing she was, she looked amazing!). She asked me if it looked good on her, and I replied with 'Yeah, you can totally pull it off', which both confused and scared her greatly!
I completely hadn't realised that idiomatic phrases such as that one didn't cross the language barrier very well - I meant to tell her that she looked great, she thought I was asking her to take the dress off!
So, just a little discussion starter, for anybody who may be interested: Have you ever had a similar experience, in which an idiom from your own language was misunderstood by a non-native speaker? I'd be really interested to hear any stories, and I hope other people might find this kind of thing interesting too! :)