Some snakes can certainly kill you, but it's rare. Partially because rattlesnakes are courteous enough to warn people who get too close (rattling) and partially because North American hospitals all know what the native venomous snakes are and have antivenom for them. Most people who get bitten by venomous snakes were deliberately messing around with them but there's a small chance that you might accidentally step on one that wasn't rattling. Copperhead bites are more common than rattlesnake bites, probably because they don't rattle as much, but they're less likely to kill.

There are only one or two kids killed by snakes per decade in the US: https://en.wikipedia.org/wiki/List_of_fatal_snake_bites_in_t...

Spider deaths are even more rare. Brown recluses are pretty spooky though.