I would say long-distance driving. Especially driving through the middle of nowhere areas and then I would worry about my car breaking down. I guess I've had it for a while, but lately I don't want to do it anymore. I had taken many long distance road trips by myself in the past, including going diagonally cross-country in the US seven times (NE & SW). There are a lot of remote areas in the western part of the US. The area I used to have a panic to drive through, other than the remote west, was driving through the New York City area. I would see cars on the breakdown that were torched and even seen some car-strippers taking a car apart in broad daylight.

I used to be such a "road warrior" when I was much younger, but not anymore. I hate myself for being like that now.