So I really can't be angry at the wood.
I was determined to get all the posts into their holes on Saturday, and I did, but they are incredibly wet and heavy (I could not seem to get any sympathy from anyone on this point--they were really, really heavy). These posts stick up about 7.5 feet, sometimes higher because I just couldn't dig the hole any deeper.
See how the neighbor's fence is leaning into our yard!
I'm installing next to my neighbor's fence, about 1 foot away, and the nails will need to be driven from that side. A tight fit. Most framing nail guns won't even fit into such a small space, but then I found the perfect solution--a nail gun that fits into the palm of my hand (a palm nailer), and it is only a few inches thick. You just drop in a nail and press it against the wood.
What could go wrong?
Coming up next: attaching the stringers and testing my new nail gun.