I want you!

This poster was created by J.M. Flagg in 1917 to recruit people for the army of the USA. Uncle Sam points at you as a viewer very directly, demanding your attention. The pointing finger and somewhat angry gaze make the whole thing rather intrusive, menacing almost.

He based his design on that of Alfred Leete, who used a similar image to address people a few years earlier, in 1914, see the "Britons" poster.

Since then, there have been many remakes of it, up to quite ridiculous ones. But the core concept remains strong: a very direct, confrontational way of addressing the viewer. You're not asking for attention; you're demanding it.