Timber Rattlesnake
Eastern North Carolina Coastal Plain.
I nearly stepped on it and it never even sang to me and barely moved it's head to look at me. I suspect it may be a female in the process of laying eggs.
I have had a large one give me the alarm right as my foot was about to land on it. If you haven't heard it in person before it sounds an awful lot like air rushing out of a small hole in an aerosol can. But in my experiences rattlesnakes are typically pretty docile and just want to get away from you. Copperheads and especially Cottonmouths are typically more aggressive from what I've seen.
I'd honestly pay pretty good money to know exactly how many venomous snakes I've come within 10 feet of and was none the wiser.
And yes, I wear snake gaiters every single day in the warm seasons. Be safe out there folks!