Fear: What, Why, When, and How

Tomorrow (today by the time this is published) I am having my wisdom teeth removed. This got me thinking about fear, and namely, how different people experience fear in different ways. (Yes, I intend you to apply this to character creation).

Take my own upcoming experience. I could be scared about being put to sleep using anesthesia, or about having a doctor I don't know making incisions inside my mouth, or about something going wrong during surgery. However, I find myself scared of how I'll be affected by the pain medication I'll be on after the surgery itself, because I am scared I will lose a certain amount of control over myself. Although right now I am not feeling nervous, I probably will be tomorrow right before I go to sleep for the procedure. If things happen as per normal, I will feel those nerves first through my stomach and those physical sensations will clue me in to the fact that I'm actually nervous at all.

So there are three main things to take note of there:

1. What the person is scared of and why
2. When they will feel the effects of their fear/nerves
3. How they will feel their anxiety

So let's talk about point one. Everyone has different core fears. One of mine is lack of control - from that core fear comes my fear and/or dislike of boats, ice-skating, letting people see me when I'm overly tired, and being put on medication which is known to make people a little crazy. If you identify even one core fear for a character you can find multiple surface fears to use in the story to torture them  to advance the character arc!

Point two - everyone gets hit by nerves at different times. They could obsess over an upcoming stressor for months or feel fine right up until they are actually facing their fear head-on. They could have "moments" for weeks ahead of time when they suddenly feel scared and then they feel fine again, or they could live with a constant sense of fear for a long period of time. When would your character be feeling the effects of his fear?

And now we come to three. People feel fear in a myriad of different ways. Some get nauseous, I get gassy, some get shaky, some just start snapping at people verbally, while in others it will be completely unnoticeable until they break down either in public or in private.
Brainstorm and figure out how your character feels fear uniquely.

I am sorry this post is so short today. It was last minute and I don't have time to add anything more to it before my surgery. 

What are some of your characters' core fears? And what are some more surface fears that stem from them? What about the timing? Also, how is your character affected mentally and physically?