* Some of the drivers are nominated by their verbally abusive spouses. The hosts will point out to them how much of a detriment they are to their driving spouses, and they actually turn around their own behaviors. Sometimes, the epiphany is a TearJerker: one verbally abusive spouse (considered the worst they'd had on the show) went on a drive with the host with his own verbal abuse being played back at him during the drive. The man was absolutely crushed to realize how bad he was and made a conscious effort to change. His wife's driving performance (to say nothing of their relationship) improved drastically.
* Aaron's graduation in Season 7. He consistently refused to graduate because he wanted to get everything he could out of rehab ''and'' he wanted to be a warning to the rest of the contestants. He was therefore the last graduate of the season. You can't help but smile when he does his final challenge (a drive on public roads) and performs almost perfectly (after accidentally running a stop sign); he is grinning from ear to ear and Andrew is quite relaxed.