Rank the special infected...

...starting with the biggest pains in the ass.

Charger: They're easy to spot and their massive bodies make for an easy target but their HP is ridiculous. You can empty a slew of frag rounds into them and they'll still remain standing. Whether they charge at you or punch you at close range, the charger depletes a dangerous amount of health in no time at all. If you're in their line of sight and you hear that dreaded charging roar, well, you had better hope your teammates are close by.

Jockey: This little dickhead would be first if he didn't have nearly half as much HP as the charger. Jockeys are, simply put, a goddam headache. Their laugh is annoying as hell, they're stealthy and trying to knock/shoot them off the survivors is a challenge in itself.

Tank: Like the hunter, tanks aren't too hard once you learn the strategies. Always have a molotov handy if you're certain you'll be crossing paths with one. The downside to fighting a tank is that if your fellow survivors are bots then you have your work cut out for you. The AI for the bots is ridiculously awful. They do not dodge throwing attacks and they will stand their ground until a tank punches them out of the way. What puts the tank higher on the list is that there will be a few occasions in which fighting a tank is an impossible battle (e.g. after you've crossed the downed door in the mall, which is a point of no return).

Smoker: These are the kings of the cheap shots. They often hide out of sight and out of reach and dash off like little pansies when they're spotted. While smokers are frustrating to deal with, the silver lining is that there is a significant lag time in between their primary attacks, so it is moderately easy to run after them and shoot them down. If you know there is a smoker around, be sure to make him your priority before pushing forward.

Hunter: Hunters are not too difficult once you figure out how to deal with them. Their growls and shrieks are easily audible so you can always tell when one is nearby. They're quick, certainly, but if you see one pounce at you then you can easily block his attack. The "push" defense stuns them for a good couple seconds, giving you plenty of time to retaliate.

Witch: Easily avoidable, but if you happen to spook her, you better have an adrenaline shot handy.

Boomer: Fat ass here makes for a nice, wide target. The vomiting is a pain, though. Once he vomits on you, however, your vision is severely compromised and before you know it, you've got a swarm of zombies all over you.

Spitter: The most worthless of the bunch. Their neon green spit makes them visible from quite a distance, they have a very low HP and their attack is easily avoidable.

Count each day as a gift; you never know when the wrapping paper's going to run out.