Teen age girls will sometimes lie to avoid getting into trouble, especially if trouble involves a whipping.Also predictable, it is easier to keep a lie going once it gains momentum than to confess that you've lied and deal with the consequences of your actions. This is especially true when you have lied in the first place to avoid taking responsibility for your actions, and have tried to avoid the consequences.
Perhaps the most predictable actions were when Abigail accused Elizabeth Proctor, and again when she accused Mary Warren. The first was simply to clear the way for her and John Proctor, and the second was simply self preservation. By discrediting Mary, she was also saving the reputation of herself and the other girls.
In the middle (predictable and unpredictable) is what happened with the townspeople. The part that is predictable is that the townspeople were mostly uneducated and superstitous. The devil was real to them and they could believe that the devil was at work because they had been indoctrinated to believe it. What was unpredictable with the townspeople was how quick they all were to confess, especially given that they were a people who took lying very seriously.
With the townspeople, the predictable elements were those where people acted in consistency with their character. Some people, the Putnamn's for instance, saw an opportunity to gain and they took it. They were basically unloving people from the start, so their actions were consistent with their personality. Similarily, the characters who refuse to confess in order to protect their honour are also predictable, at least from within the perspective of the culture they come from. They would consider themselves damned if they lied, so from their perspective, they were giving up their mortal lives to save their immortal ones, their souls.
Unpredictable elements are the ones where people said or did things that they didn't expect to turn into trouble. For instance, when Giles Corey mentioned his wife reading, he would never have thought that it would get her arrested. Similarily, when Proctor said that Elizabeth couldn't lie and she lied to protect him, neither of them knew that it would damn them both.
Well, for one thing, the group responds in a predictable manner as they all fear Satan and witches are certainly from Satan. They are products of a very strict religious community, and when people don't understand things (such as paranormal events) they band even more tightly together. Mass hysteria evolves quickly from there, and it takes awhile for reason to again take hold.
Had they listened to the voices of reason--Rebecca Nurse, John Proctor--instead of those silly little girls, none of the deaths would have occurred.
On the other hand, Abigail Williams knew exactly what she was doing. People act in unpredictable ways when they are protecting themselves. She was working hard to cover her own tracks--the love spell to make John Proctor fall in love with her, the attempt (and success) of getting Elizabeth Proctor accused of witchcraft in order to get her out of the picture, and the protection of the reputation of both herself and her uncle, Reverend Parris. It is only after the truth is unraveled a little at a time that she steals from Parris and disappears into the night after manipulating the other girls into doing her bidding while wreaking havoc on an otherwise quiet and uneventful town.
So, being part of a strict religious community would cause individuals and groups to react predictably in their faith, coming together against an unknown evil in the hope of extinguishing it. Individuals within that religious community act unpredictably in order to hide their not-so-religious actions and thoughts in an endeavor to keep their sins from being discovered. There's a beginning...hope it helps! Good Luck!