Why do difficult passengers unsettle me when I drive?

The driving is the easy part. You know the roads and the car. What throws you is the person in the back seat you cannot predict, in a space you cannot leave. That is a fair thing to find hard. A difficult passenger is usually carrying their own bad day, and it spills onto the nearest person. That person is you, but the mess is not about you. Seeing it that way lets you stop taking it personally and start handling it plainly. Pick one steady line to fall back on, something like, I hear you, let's get you there safe. Say it and mean it, then let the rest go. You do not have to fix their mood. You only have to drive the car and stay yourself while you do.