That's true about the hair grooming, I seem to have inherited my Grandad's fondness for Brylcreem, and have noticed it tends to leave its mark on any headgear you have on at the time! The charity I work with doesn't greatly appreciate me for it, Brylcreeming up their uniform headgear, but it does mean nobody ever tries to blag my helmet after I've used it! The Brylcreem probably does go some way to ensuring your hat stays on!
On a related note, I seem to recall seeing a TV interview with Jimmy Perry, who came up with the series Dad's Army, about a fictional Home Guard platoon, and apparently the angle that various characters wore their Field Service caps was an area of uniform that they put great attention into, in order that their standard of dress suited the character's personality etc. For example, Sgt Wilson was intended to be a sort of scruffy-aristocratic type and let his cap hang on at a ludicrous angle, and have his collar and cuffs open etc, Pte Walker was supposed to wear his uniform in flamboyant, un-military ways befitting the local spiv, and supposedly they worked out early on that it suited Pte Pike's silly, naive character to have his cap pulled right down over his eyebrows.