I don't have any particular reactions to nerves, but I do have something to contribute that's on a similar vein.

Whenever a problem situation comes up, I tend to have a reaction inversely proportional to the severity of the situation.

I blow my stack when a package I'm expecting doesn't arrive the day I'm expecting it. Yet when my great-grandmother was diagnosed with terminal cancer, and again when she passed away, I was the calmest person in the family. And before that, in 1997, when I lost my right eye due to retinal detachment, I was the only person who wasn't freaking out over it. It wasn't shock; I knew what was happening in both cases, so I was braced for it. While everyone else would be like "Oh God, this is terrible, this shouldn't be happening", I was like, "Oh well. It's nothing that can't be dealt with." I just have an odd way of keeping my cool when something serious happens, despite having a tantrum like a 4-year-old when a minor thing happens.

-Trunks (Cannot find server!? Ahhh! I wanna read the page *now!* *explodes*)