You know, it is just a passing thought so I have never put much thought into it as you have. But two of them resonates with me.

The thought of driving into incoming traffic.
The thought of standing by the edge and jumping off.

I have had that thought on more than one occasion. Its like I want to take the wheel and just jerk it to see what happens. What stops me is I have been in many accidents before and I know the outcome. But I do still get that thought in my head,

As for the jumping off from a high place, I don't know where that comes from.

To me, I think its the unknown. The "what if" that we all think about. You're right when you say its not talked about. I guess I have never told any therapist or psychiatrist about those thoughts for fear they would lock me up for being suicidal.

However, I do have a pretty good therapist, one that I have known for 7 years. I will bring it up in next session if I remember that is. I see him Wednesday. I will ask him about it and try to remember to come back and post to tell you what he thinks,