Thanks to all for participating and the votes. I took the 'burden' of winning this weeks WET, by starting
WET #40: Creepy
I think it was hard to vote, due to the submissions being quite different (which is of course the fun of the challenge) and therefore difficult to compare. Martin (Stiga) got my #1 vote because it showed multiple hats and expresses the variety of things people put on their heads. The submissions by Rob (RDWP) en Stephen showed head gear that used to be worn in past times on a regular basis, making it a bit less gimmicky.
Some of the other head wear (the clown mask, the goofy mask and viking hat) fully fitted the theme, but my preference went to more 'realistic' hats. None of those photos were so strong they could convince me otherwise to pick them over my top 3.
To me Levina's photo was more a photo of a photo than fitting to the theme and showing things people wear on their head, although of course the original photo does show that. But then Levina should have submitted that original photo

.
The photo submitted by Inphoto was intriguing and probably the most 'photographic' submission this week (being far more than a 'snapshot'). Don't know exactly what I was looking at, but it did not seem like something they would actually wear on their head, just holding it over their head, so to me that wasn't a full fit with the theme. I do however see why it was submitted given the theme.