CAPS NOT HATS
The cycling cap is the cyclist's crown. It is both form and function, keeping sweat or rain out of your eyes, shielding you from the low sun in the Spring and Autumn, keeping your head warm, and of course, making you look damn cool in a way that non-cyclists just don't understand.
For cyclists, lüft (german for air or space) is essential to perfecting the cafe look. Too high on the head and your cap is likely to blow off and ruin someone's meal, too low and blood flow will be restricted, reducing your chances of an intellectual post-ride coffee debate. As a rule of thumb, lüft should be proportional to brow size.
Disclaimer: these cycling caps should only be worn with cycling kit, and when one's helmet is not present, close adherence should be paid to obtaining correct lüft.