Thank Him in the parking lot before you know how the interview went.

Gratitude offered before the result is a different act from gratitude afterward. Waiting for the outcome makes thanks conditional on getting what you want, which quietly turns the relationship into a scoreboard. Saying it in the parking lot, before anything is known, is a way of settling who you are dealing with rather than what you are receiving.

Try it after the next thing you are nervous about, while the outcome is still open. Say what you are thankful for regardless of how it went. Notice how much calmer the waiting becomes when the verdict is not carrying everything.