Many snakes serve a good purpose, don't kill the non-venomous ones. Slit eyes vs round eyes.
+1 ...but don't agree on leaving the rattlers (or other venomous ones (but in Az it's primarily rattlers) alone. Anywhere where you/your loved ones or others tromp regularly, - letting the fanged ones go just leaves them as a problem for someone else, their kids, etc, or you to revisit another day under even more unpleasant circumstances. I don't get that.
Anywhere near my domicile or fave fishing hole where my daughter, nieces, nephews or dog might encounter - need to be gone.
+1 to someone else's hatband comment
The thought of water mocassin/cottonmouths do give me even more heebeejeebees; glad we don't have to deal with them!
Want rodent (or rattler!) control? Get a King or Bull snake!