... heading down a staircase, imagining what the fall would be like and wondering which time it will actually happen;
... seeing a large nail or other sharp protrusion coming out of a wall and thinking about the scenarios for your head hitting it and having a major injury or dying;
... waking up in the middle of the night with some strange symptoms, looking them up to make sure it's not a heart attack (even though you've looked them up many times before), seeing you don't have even the unusual symptoms of a heart attack, but still not being able to go back to sleep because what if it is, in fact, a heart attack;
... having your boyfriend not answer your text for an hour and, even though you know he's probably just taking a nap, letting the fear freak you out - being sure that he's injured or dead;
... looking on a tracking program (our whole family does it) late at night and seeing that your adult daughter is at an unusual location and, even though you look up the area and find out a restaurant is nearby, can't let the obvious scenario be that she's eating there and instead thinks something happened to her;
... checking your bank balance and seeing that, for once, you made enough money to pay all of the bills for the month with a little leftover but all you can think about is that something could still happen to the car to wipe out that extra, plus more;
... noticing that someone you work with is treating you differently and, even though you are 99% sure that it's something going on with them (like a family issue, etc), you just can't shake the fact that maybe it's something you did;
... going to a party with people that you know and love but still find that once you get there, you are paralyzed with fear and hide out in an unused room for the majority of the event;
... overhearing that a diagnosis you have could possibly lead to another condition that could possibly cause major vision or hearing impairments and so you decide to start learning braille and sign language, just in case (this was at about 10 years old);
... observing that something fragile is near the edge of a table and automatically seeing it crash;
... watching your pet walk differently and have 20 different horrible outcomes (both with the pet and financially due to vet bills) even though he jumped down from a table funny last night and chances are huge that it's just a sprain;
... walking on an uneven surface, such as cobblestone, and not being able to stop thinking about how injured you could get if you fall...
Every one of these scenarios is something that has happened, or continues to happen, to me. I have come a long way in that now I usually am able to recognize how crazy the thought is and not get totally wrapped up in anxiety over it, but it's still there and is often still a fight.