Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Distant and a Little Disdainful
Bayard's telling the story with the benefit of years between him and the events, in the grand ole tradition of the Rooster from Robin Hood. That means that he's got some perspective. He's not trying to tell you what's happening as it happens, which could be a little stressful.
No, he's had the chance to mull over this stuff for years and decide just how he's going to present his story to us. Even at the end of the novel, where Bayard's already old enough to be off studying law, he still shows us the way that hindsight's 20/20:
It was just after supper. I had just opened my Coke on the table beneath the lamp; I heard Professor Wilkins' feet in the hall and then the instant of silence as he put his hand to the door knob, and I should have known. People talk glibly of presentiment, but I had none. (7.1.1)
That "should have," along with its great pals "could have" and "would have," is the great marker of regret. The Bayard in the novel, kicking back with an ice-cold Coke, is blithely oblivious to the bad news on the way; the Bayard-narrator, as he retells the story, knows about the terrible truth and lets us know that it's coming.
That distance has also given him time to get a little judgey, and Bayard lets his disdain for the violence that painted his childhood slip in every now and then. Take, for example, this description of his dear old dad:
Then I began to smell it again, like each time he returned… that odor in his clothes and beard and flesh too which I believed was the smell of powder and glory, the elected victorious but know better now: known now to have been only the will to endure, a sardonic and even humorous declining of self-delusion which is not even kin to that optimism which believes that that which is about to happen to us can possibly be the worst which we can suffer. (1.1.26)
Check out the use of tenses here (bet you didn't know that grammatical tense could carry so much emotion). Bayard starts out in the past tense to describe what he used to think about his dad, considering him a war hero, then moves into the present to say what he knows now.
And the present ain't as glorious as the past; nowadays he thinks of his dad as a deluded, even decadent figure. That attitude toward the past carries over to his entire society, and Bayard's tone lets Faulkner convey it.