Well, not the best choice, as this particular story is more scary than fun. But have at it.
I was working in Belgium at the time, and I went down to Paris to visit an old friend who was living there, we were high school classmates. So I got to Paris and we went wandering around for the weekend, speaking in Basque most of the time. And then I went back to Belgium by bus, with the only "incident" of having misplaced the ticket and almost having to spend the night at the bus station since there were no more open seats that night. Luckily, I found the ticket in the nick of time. I didn't see a single policeman (up close).
A couple of days later, I read on the news there had been a shoutout in Paris where a policeman had died, attributed to ETA. French police were out for blood, the faces of the terrorists were all over the news as they requested cooperation to locate them. However, as it turns out, the "terrorists" weren't terrorists at all. Some off-duty French policeman claimed he had heard 3 guys speaking in Basque at a supermarket, the police got their faces from the supermarket's cameras and there you have it, pictures for the media. These 3 guys turned out to be Catalan firemen on holiday in Paris, which means they were almost certainly speaking Catalan and not Basque (which is seriously different, may I add). They heard of the whole thing when family called them to tell them they were on the Spanish news as "most wanted terrorists", so they holed up at their hotel room and contacted Catalan authorities to get things cleared out.
Now, this is somewhat funny, but I suppose you can see where this is going, right?
That could have been me. I was walking all around Paris speaking in Basque for 2 days, after all. These guys got away because they weren't even Basque and it was a very clear mistake. But what if it had been me? Furthermore, what if I couldn't find my bus ticket and had to spend that night at the station, would that have counted as an Alibi? I could have awoken one day to be the most wanted terrorist in two countries and gone to work just like that because I wouldn't have known. I'm scared of Spanish police, with torture and whatnot, and while French police is likely not the same it still gave me cold sweat.
So this is the scariest police-related experience I've ever had. Nothing actually happened, but I assure you when I read the news and imagined what realistically could have happened to me... it was damn scary.