Ahh I can offer some insight on why Jeb seems to be high all the time.
He is the pilot!
The crew AI is the same for all of them, but they have different personalities. Their personalities are defined by 3 attributes: Courage, Stupidity, and whether or not they're the pilot.
Jeb is 0.5f brave and 0.5f stupid, but he's the pilot, so what the others would find terrifying, he finds entertaining.
Bill is 0.5f brave and 0.8f stupid, and he's not a pilot. So he gets scared, but being dense as he is, he doesn't realize the danger as much.
And Bob is 0.1f brave and only 0.3f stupid, so being by far the least stupid in the bunch, he quickly realizes how near they are to being blown up, and panics really fast.
There are other factors that make the crew panic as well... nearby explosions being one of them. They are already traumatized enough so that hearing a nearby explosion will make them all have bladder control problems.
Later on I'm planning on adding a Nausea Tolerance parameter to their AI, and have them become nauseated under high angular velocities and possibly space sick as well, when under microgravity conditions... They could visually turn green also, if they weren't green already.... hmm, maybe they should turn yellow :lol:
Also, I plan to add different types of Kerbal crew... right now all we have is the generic, Orange suit wearing, crewmembers. Later, the idea is to have Pilots (in orange), Engineers (in blue), and Mission Specialists (or scientists, in white)... each of those would have different personalities... for example, pilots are braver and have a high nausea tolerance, but they're stupid; scientists are smart, but cowards and get sick really easily; engineers... not sure yet... maybe they're somewhere in between, or something else.
Cheers