My accents when speaking foreign languages are so good I have been mistake for a native speaker on a few occasions...
Unfortunately my ability to understand the other speaker doesn't always match at which point they learn I'm not as fluent as they thought! 
This has caused some confusion at times
However it has also proven interesting when I CAN understand what people speaking in other languages are saying when they are assuming those around them can't understand...and they're saying what they really think!
If I'm in a mischievous mood I'll then say something in "response" to what they've said, usually in their language.
I once told Des O'connor that he looked like Des O'connor.
I was present when someone did this to another celeb, celeb took it in good faith and said
"I know I get that all the time"
Celeb has a VERY well known voice and accent
Person then said
"Wow! You even sound like him, you could get work as a lookalike" 
and gave me one of Fergie's hairclips that had broken and wanted me to glue it together!
Was it a fergie bow? 
I've had sm "likes" from all 4 of the central charmed actresses, not on the same subject different stuff