Mailbag: “Mirage Not Oasis” Edition

I have never understood momentum swings and/or how a team can go from being completely dominated and looking inept (like the first 3 quarters Friday) to looking like a completely different team and stringing together multiple scoring drives (like the 4th quarter Friday). Another great example might be the Seahawks Packers gazillion interception NFC championship game a handful of years ago. I get that there are adjustments that happen, but why does it take 1/2 or 3/4 of a game? Or that a team with a lead might shift to a prevent defense and let the other team back into it (happens in the NFL all the time).