Can you somehow predict behavior?

Yes, my own & those closest to me. For example, I know if I bake my sea salt chocolate chip cookies, it'll be gone in 3 days. 🍪

And I know if I use the word "cute" with you, I'll get an offended reaction from you. 😝

[i]I Know why everyone does everything.. thats a start![/i]
and no I am not going to try to tell you that here..
BUT the most basic tool is
what does the ANIMAL that that person inhabits want.
the brainiac part of our mind will find some way to give the animal what it wants

Only my own and my dog's. With everyone else, it's a crap shoot.

No but Behavioral Scientists can..