Cliff, as nice as it can be, I have been FORCED to wear a hat for years, and it was absolute VIOLENCE on me.
It spoils any kind of hairstyle, and of course you always have to be impeccable. It gave me the rash, so I used to have a red mark on my forehead for hours. We were forced to use it even at the Maldives with 40C or in Mexico etc. Some porridgebrains of ChiefPursers even wanted it to be worn starting from the hotel room (of course nothing of this happened on my flights after I became CSD in that airline). When you needed the silly thing it was always nowhere to be found. And in case of wind... It was not an unusual sight to see a C/A running after the silly thing on the tarmac.
The one and only hour in my life I appreciated it was in Hannover, when one night we were left stranded by the hotel transport that never showed up, and we used it for a photographic set where it starred as coin collector with CSD(moi!) and Purser (Stefano, most handsome Purser on Earth!) posing as beggars.
I believe you should feel comfortable in an uniform in which you have to work for hours in an hostile environment
I know it is much much easier for male C/A, so maybe you don't realise at what point it can be more difficult for ladies, with high heels, hosiery, tight clothes, makeup, hairstyle to take care of, but please, have mercy, not the hat on top of all that!!!