While playing half life 2 for the bazzilionth time, i reached the end of ravenholm, in the mine just before that decapitator mine cart when I hear that all too familiar rattle, I spin around and blast the source of the sound, who had been sitting conveniently at eye level and continued my merry way. Just as i exit the room, i hear a loud explosion and am smacked against the wall. Confused as to how a combine soldier sneaked down here to grenade me, i look back and see a bunch of scorched metal shard lying around. Then it dawns on me that in my urge to get rid of the tiny, camouflaged alien rodent, i apparently missed the bright red barrel it was sitting on and had been in that room for my 10 or so previous runs through the area too, or at least failed to register that bright red barrels are not to be shot at at point blank range.
Furthermore, I realized that 90% of my use of grenades and thrown explosive barrels had been against them and not the zombies, which i rarely used anything heavier against then thrown sawblades or bricks. Well, some double barreled shotgun blasts against the carrier zombies. Which were always the first zombies i shot at.
So now I a wondering, how did Valve create an enemy whose destruction I prioritize over anything else, even my own survival? They aren't particularly dangerous, in fact they can't even kill me directly except by gently tapping me for half an hour until i fall off a ledge, they give ample and very clear warning of impeding attacks and never ambush, their stature isn't any more imposing then that of my cat and they aren't any harder to deal with then their regular stubby legged brethren.