Men's hats in TV period dramas

1. Worn over the tops of the ears. 
I first noticed this one with the hero's batman in the adaptation of Sebastian Faulks' Birdsong. In the style of youths today who wear boxfresh baseball caps over the ears and low on the brow, with completely flat peaks. 

Which brings me to my next point:

2. Ironed flat brims, like man on the Sandeman's Port label's hat - a flamenco dancer?

Exclusively on Foyle's War, this one, throughout the different series, as a kind of trademark.
Looks ridiculous, and just like all the styles I comment on here, absolutely wrong - no-one ever wore their hats like this. 
The brims had some curl to them when they came out of the factory, never mind when people wore them. 

Which brings me to my next point:

3. Brims curled the wrong way. Pulled down at the front AND the back. 
This is the way people often wear hats with brims now, but attention to old newsreels and crowd photos will reveal to wardrobe people that this style was less often seen, and when it was, it was more often in America. The general rule is, up at the back, down at the front.
The other thing that that attention will reveal is that trilby or fedora hats were not so very common in Britain, right into the 50s.

WBMTMNP:

4. Everyone wearing trilbys, everywhere, all the time.
Once again, study of contemporary source material will reveal relatively fewer men in any crowd wearing trilbys. 

It was more often flat caps for working class men, bowlers for clerks, the middle class and anyone in a supervisory position (and nearly all plainclothes coppers), and toppers for toffs in the city or at formal events. Trilbys or 'soft hats' were for off duty, perhaps seen as a bit flamboyant or bohemian, what was worn in Yank films, an attitude that persisted until after the war. 

The most absurd example of this being on Foyle's War again, one of the Cold War Foyle's. Foyle has to visit Oxford, and we see one of the Inns of Court in London standing in (I think Middle Temple) for an Oxford college. Hurrying between the different entrances and criss-crossing the court, we see dozens of men wearing undergraduates' short gowns, EVERY SINGLE ONE WEARING A TRILBY. No, no, no. Students did not wear hats at or inbetween lectures, and even if they did, they wouldn't all be trilbys anyway.

WBMT My Final Point:

For people who dress up in 'vintage' clothes: 
Men did not usually wear hats indoors, and definitely not at dances or in nightclubs.