coffee no. 98

One of the phenomena that really astonishes me is somebody-looks-at-you moment. The moment when some person attracts you only with their eyesight, or vice versa. I have tried this trick many times, always with the same result. Sooner or later people realise that they are being observed, even if they are sitting in another corner of overcrowded cafe. Even if they are preoccupied with the conversation, with reading a newspaper, with eating, etc. They behave as if they have been stung suddenly and for a second they interrupt all their activities only to send you kind of why-the-hell-are-you-staring-at-me expression. Do-I-know-you?! Have-I-got-dirty?
I am very curious how does it work. Do our eyes send some invisible waves that can put an ephemeral spell on the others?...