Dun, dun DUNNNNNN!
Imagine you are in a nice, warm, comfortable house and there is a storm outside. You know you will have to go out in that storm. You suspect that it is cold. You can see that it is windy. You KNOW you will get wet. You prepare. You get your coat zipped up, your hat pulled tight, your gloves, scarf, maybe even rain boots and an umbrella. You make sure you are ready to face that storm before you ever go near the door. You are as ready as you are ever going to be.
Then you open the door.
No matter how prepared you are, no matter how accustomed you are to getting wet, you still flinch. You still turn your head from the wind and rain. You may even hesitate on the threshold. Maybe you take a deep breath before plunging out into it. Then you run, head down, shoulders hunched to wherever you are going.
Why do we do this? What harm is that rain going to do? Is the wind really so bad?
It isn't the storm that makes us brace ourselves. It is the change. It is the shock of going from a warm, dry, comfortable place to a cold, wet, miserable place.
That is what it is like in a deployment. You prepare yourself. You know it is coming. You might dread it but you know it won't last forever. But when that day finally comes it slaps you in the face like a cold, hard rain. You gasp, you hesistate. Then you duck your head and plunge into the storm.