Mauzeraut

There's a lot of things wrong with the rage virus scenario. The biggest flaw that I see is that it follows the rabies scenario. There's just one problem with that: Rabid animals do not like rabid animals. It's not as if everything that isn't rabid is "Team Blue" and everything that is becomes "Team Red". There would be a lot of red-on-red murder going on, which would greatly diminish the staying power of the disease, and not just in the case of rage virus, but pretty much every zompocalypse scenario... yet every movie I see on the subject implies this. The other aspect is human psychology and brain chemestry is incredibly complex. It's one thing for a fungi to be able to control ants over millions of years of evolution (ants are reletively simple by comparison), it's quite another to force a human into specific behavior. It's possible to induce insanity and increased aggression, but it wouldn't be perfect. The most valid human-extinction scenario from a pathogen is something that would be ridiculously virulent and stealthy that causes either sterility at 100% effectiveness (Children of Men scenario, and 100% is unlikely... even ebola and black plague have survivors) or symptom-free death over an extremely long period. The latter would almost certainly have to be an engineered chimera, which would be almost useless as a bioweapon as it would work too slow to be militarilly effective and pretty much garaunteed to bite you in the ass for using it... although if we were attacked by extra-terrestrials this might be something you'd see. Valid bioweapons would be designed to burn fast and hard, but would be unlikely to cause an apocalyptic scenario ("Outbreak" has a good example of a fictional virus that might be capable of this). Other scenarios include non-biologics like a Von Neumann-esque nanovirus ("Grey Goo" scenario) or non-living organisms unaffected by defensive immunities (Andromeda Strain), but those are even less likely.