I've been assigned as a gunner in a tank around a month ago, and since then am going through a series of lessons and demonstrations to learn my job in the tank.
Basically, I'm the guy who turns the turret, raises and lowers the cannon, and of course, evetually takes aim and fires the shells.
Being a gunner is the biggest responsibility in the tank, after all, if the tank misses its target, I'm the one to blame. Guys who have gone through advanced training say that the tank commander is usually mad at the gunner, and is basically the commander's bitch (I am not allowed to shoot, nor perform many other action without permission from him).
Nevertheless, being a gunner is pretty damn cool, taking aim and turning the turret is fun, and then there's this shitload of modern advanced systems in the tank to play with, that obviously I'm not supposed to talk about.
Well, what can I say? Slowly, I'm studying the Merkava mk.4, and IMO, that tank kicks ass. It's not like I'm overexcited or something, but after all, there's this thing that satisfies me, every time I think that I have an opportunity to fight in a war machine that costs millions, and is one of the most powerful weapons in the world, it's not something anyone has an opportunity to do. And that's my little piece of pride.