Let's say you have been stuck in a single room for the better part of a week, without electricity, with just a cell phone and a couple of batteries, and outside the room are hundreds of enemy troops who just can't wait for any excuse to put a bullet in you, and there is no probability of a friendly force driving them away. In the meantime, what little infrastructure your country has, like housing developments and roads (ever see what a tank does to a city street?) are being destroyed.
Wouldn't that make you just a little bit irritable?
The only thing you should feel when shooting a terrorist: Recoil.