How to adjust defense at halftime if doing great...

I watched soooo much game film, and it seemed to pay off. The defense had a perfect half. At halftime I guess I let hubris take over and made no adjustments. The other team adjusted and dominated. We lost.

What adjustments do you all make to defense at halftime? Especially if it's going well. If I go watch the tape, I'll probably see my mistake, but in real time it's almost impossible.