I've had a few incidents where i was a little freaked out but nothing like my experience i had several years ago.
5 of us in one car were headed to Jacksonville from Tampa. We didn't start driving until around 7pm. On a lonely stretch of road south of I10 we're cruising along goofing off, laughing, telling jokes and what not. There was hardly anyone on the road that night. The road we were on was a 4 lane divided highway. Sometimes there was just grass separating each set of lanes, sometimes there were trees and sometimes there was a paved section for turning left or right or making a U-turn.
As we're all in a good laugh about a joke we all stopped laughing at just about the same time. From across the grass coming from the other set of lanes was what appeared to be a cloud of steam or fog. It seemed to have it's own light source, kind of like glowing in the dark without the green hue. At first it seemed to be shaped like a blob but as it approached our vehicle it was more human sized and shaped. It headed straight for us at an angle from the other side of the road. All this happened in a matter of seconds, maybe 5 to 8 seconds. As soon as the driver realized it was going to hit us he slammed on the breaks and veered off to the right. What ever it was made a B-line straight for us and flew right over our windshield. We ended up on the right shoulder of the road all freaked out with huge eyes and neck hair standing on end. We asked each other what the heck that was even though we knew none of us would have an answer. After a few minutes we got back on the road and continued on our way.
About 13 miles up the road we saw some police lights at one of those paved sections where you could cross over to the other side of the road. As we got closer we could see a mangled up car in the trees just before the paved part. As we passed we could see a person on the paved part of the median, covered with a sheet. The last 45 min of the trip was pretty quite. I don't know why but none of us talked about it at all after that night.
Clearly we all thought it was the ghost of the person who died in the median that night. But who knows, maybe it was a white plastic back being flown by lightning bugs or something. What puzzled me was how what ever it was was taking into account our velocity because from our perspective it was always coming at us in a straight line. That's why we didn't think it would hit us until it was right on top of us. Judging from where it was and where we were going i was sure it would fly across the road way behind us. But it kept it's course, straight to our windshield.
Aside from that my dog has had me freaked out a few times.