Swedes abroad

It is amazing how easy it is to tell a Swede among other nationalities abroad! I have been sitting at the same place in the airport in Lisbon now for almost two hours and noticed several times how easy I can tell who is Swedish- I can tell from afar. This far I haven't mistaken once. However I can not exactly tell what it is, but I see it from a long distance. I wonder if people just as easily can tell that I am Swedish!? And if other nationalities spot their countrymen just as easy. Please let me know!