This saying uses a play on words with “a head” and “ahead”. The wisdom we can take from it is the advice to smarten your appearance and project your personality with the style of hat that you wear. You need to pick the one that tells people who you are or want to be. Be realistic only John Wayne could be John Wayne. If in doubt ask a candid friend.
I’ll eat my hat
This oath is usually not meant seriously but in the days when many hats were made from leather, and starvation a possibility, eating your hat could stave off hunger, and perhaps provide a little nourishment to keep you alive. The thought of eating a woolen hat doesn’t bear thinking about.
As mad as a hatter
At a time when mercury was used to treat hats the effect of the fumes was literally to make people suffer trembling and seem unstable and appear to go mad so this saying was once very relevant. Perhaps they even had a go at eating their hats, poor souls.
Keep it under your hat
This means keep something you have been told to yourself; it is for your ears only.
A good head will get itself hats.
If a hat is a badge of office or sign of success then someone with a good head, a clever person, will get that hat. Hats often tell us a lot about their wearer such as their rank in the military or social position. Cowboy hats can be worn by anyone but the more expensive brands will indicate that the owner is doing well.
To go cap in hand
Doffing your cap or raising your hat is a way of showing respect. Gentlemen raise their hats to ladies and this is said to come from olden times when knights in armor would raise their visors so that the ladies would not be intimidated by them.
The classic concept of a cowboy is a man of gentlemanly character who respects ladies and will raise his Stetson in polite salute.
The expression “to go cap in hand” is mostly to indicate that the person has to show humbleness to whoever they are dealing with.
To set one’s cap at
This is used of a girl who hopes to win the affections of someone she fancies. Putting on an attractive bonnet to catch a man’s eye was a good tactic in the 18th century when ladies wore long heavy dresses. Their white linen or muslin caps needed to be tied in place with ribbon and could be set at a jaunty angle.
A pretty, pink, cowboy hat might be used to this effect today by a cute girl who hopes to make an impression, especially if the crowning glory of her hair blends harmoniously.
To get a feather in your cap
In Native American society to be awarded an eagle feather was a recognition of a brave deed. Many old pictures of braves wearing “Boss of the Plains” Stetsons have a feather in the hat band. Scottish Highland Chiefs are entitled to wear an eagle feather in their bonnets.