Whenever I hear people talking about 'deadly black widow spiders' (by that, I mean the genus Latrodectus in general, any of the true widows), it's true the bite is HORRENDOUS, and it hurts like a motherfucker, all over, there isn't a muscle in your body that doesn't get pushed passed the point of screaming, and towards begging for death, but it isn't likely to actually kill anyone, unless they are already sick, very young or very old and go untreated, a healthy person is very unlikely to die in this day and age from the venom, whilst alpha-latrotoxin is on a weight for weight basis, considerably more lethal than that of at least some of the cobra snakes, they have tiny, tiny fangs and not very much OF it. And besides, given the invention of antisera raised against Latrodectus venom (which is probably polyvalent among any of the true widow spider genus), there is very little reason anyone ought to die from a bite, suffer, yes, been there, done that, but die? no.
And the primary defense instinct is to run and hide, it's only in extremis when they will bite a human, generally if undetected in clothing or bedding and pressed against the skin. Or, as I found out, at least in Latrodectus geometricus, brown widow, the females seem to get PISSY when they've just laid eggs.
Even a country isolated and unable to administer antisera against the venom of Latros, you'd have to be pretty badly fucked already to be at serious risk.
They don't really GET pissed off, most Araneomorph spiders don't seem to have that bad of a temperament, even Sicariius spp. have been reported as relatively docile in captivity (if one DOES bite you, you are SO fucked, they are related to the recluse spiders, but the spiders are MUCH bigger, perhaps the size of a red-kneed tarantula, but a lot flatter of build, and their venom is similarly based on sphingomyelinase-D, and acts as a flesh-rotting cytotoxin, and quite likely the deadliest spider known to science in terms of venom weight lethal dosage, and definitely nastier, at least if one recovers from most spider bites, there aren't likely to be permanent sequelae, but necrotizing toxins that destroy flesh, are just nasty.)
It's the big Mygalomorphs that seem to be the pissy ones (Araneomorph and Mygalomorph refer to fang orientation, the former, exemplified by widows, recluse spiders, orb-weavers have jaws that come together like a pair of sideways-oriented pincers, the latter have generally larger builds, and downward-stabbing fangs that are oriented like a pair of downwards-thrusting daggers, like funnelwebs (Atrax, Hadronyche and....fuckin' buggrit...Al, Ren, MOSW, what was that recently discovered third tribe of Hexathelidae funnelwebs in oz? discovered a few years ago, not too long back, can't for the LIFE of me recall the damn family name, and no, I do NOT mean Missulena) Very aboriginal-linguistically leaning binomial name for the family. And same sort of fang configuration as the Mesothelids, very, very primitive, non-venomous sister group of spiders, perhaps dating back to when spider and scorpion lineages first diverged, given they are the only group to retain segmentation of the abdomen, although reduced to a series of plates.
MOST araneomorph spiders tend either to be small, or fairly docile, or else non-hazardous to humans, main exceptions being Phoneutria (brazillian wandering spider), which have both a potentially deadly bite and a near legendary mental-case temper, and the Sicariids (Loxosceles, Sicarius) with their virulently necrotic venom, the chilean recluse, L.laeta is apparently particularly toxic, and fatalities have occurred after bites from L.laeta, whilst their Sicarius relatives, are thought to considerably outdo the native ozzy spiders in terms of sheer 'you are royally fucked' if you get bitten, AFAIK no antivenom is available, they are not noted to be severely bad-tempered.
(Note-recent reclassification of many of the genus Sicarius sensu stricto, has resulted in the removal to a separate genus, Hexopthalma, which appears to be the sub-group containing large Sicariids with highly potent necrotizing venom.
