Firefighters work uniforms may be more of a yellow and orange, but let's face it: they are known for the colour red. Red on the flag is said to represent valor and hardiness. Valor is defined by great courage in the face of danger, and Hardiness means having the capability of enduring difficult conditions. Those two words fit my mind's eye's view of firefighters perfectly. Those two traits would be absolutely necessary when going into a burning building.
Doctors, once again, wear scrubs or something close to them, but they are known for the long white coat. White on the flag means 'purity' or 'innocence'. This fits them as well, as the last thing I think of when I think of a doctor is 'dirty'. Even the places they work always look so clean. Not to mention that their entire job is to help others keep their bodies pure. You may be saying "But what do doctors sacrifice?" Well, they sacrifice a LOT of time and money on constantly learning the new medical techniques, so they can become very easily stressed and may miss very important social occasions in order to make sure they are always prepared to help the people who need them. Not to mention all the disgusting things they must have to see in a lifetime.
Police are blue through and through. Their uniforms, their cars, even some of their buildings. The flag's blue stands for vigilance, perseverance, and justice. Those words are so definitive of cops, I guarantee you that you can't watch a cop movie without hearing one of them said by the chief. Policemen and policewomen are always on task and ready to help preserve the peace. Even when they are off duty, they are on duty. I've made friends with a few officers of the law (literally not sarcastically), and in all my experiences with them, they have proven to be very fair purveyors of the law.
So thank you to anyone and everyone who has ever sacrifice anything for the sake of another. You are awesome and deserve to be recognized far more often than you are.
Thanks for reading!