These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Big Lipped Alligator Moment: The "PANCAKES!" scene and the rabbit surgeon. Big surprise the first one was added in at the last minute when Eli Roth saw the little kid practising tae kwon do.
Some people also considder the impromtu sex between Paul and Marcy one of these, as it seems so unlikely that people in that situation would actually start screwing. However, it is probably more blatant Fanservice then Big Lipped Alligator. Besides, it also has reprecussions in the plot mainly, Paul contracted the disease from mixing bodily fluids with Marcy, who was infected. Also a deleted scene foreshadowed it a little where Jeff was sleeping alone while Marcy slept next to Paul.
Inferred Holocaust: The last shot is of the first shown victim lying in the river and bleeding into the water. It pans over to a truck of bottled water, presumably filled with Cool Clear Water (see above) from the river.
The ending animation shows a trucker drinking Down Home Spring Water. He pees in the bottle and throws it at some dumb kids in a convertible. The kids are heading to New Orleans for Mardi Gras.
Viewer Gender Confusion: The "Pancakes" kid is a boy, named Dennis. However he has very long hair and is apparently prepubescent, so many people mistook him for a girl.
What an Idiot: Winston. Aside from being creepy as fuck, he does not seem to think clearly either. A sick and disoriented Paul encountered Winston partying in the forest, and knocked him out when he heard that all infected persons are to be shot on sight. He then stumbled onto the highway, and a truck-driver took him to that local doctor's office, where the police located him. As he was too sick to talk, he could not communicate to the officers that one of the infected bodies had fallen into the local water reservoir, and hence infected it. To find out what he tries to say, the doctors advise that the police brings him to the county hospital, who actually has the capabilities to treat the flesh-eating bacteria. Deputy Winston is chosen to transport him there. Yet, he is vengeful for being hit over the head by him earlier.
You'd expect: That he will complete his task without hesitating. Paul is quite possibly the key for scientists to analyse this virus further so they are prepared for future infections. Apart from that, Paul still has something very important to say.
Instead: He gives a shit. He is only out for revenge, and dumps Paulin the closest river. And that was bloody stupid. He pretty much is solely owe for everything that happened in the sequel and after that. He actually dumped a guy with a highly aggressive and quickly spreading bacterial infection in a river, which co-incidentally leads back to that town and the Cool Clear Water bottling factory. He should really have known that. Apart from that, there wasn't much of a reason in the first place. Oh, and he got away with it.