the three witches: about as clear as case law

Okay so back to my love of the supernatural…there’s one thing I’ve noticed about the witches that has lead me to a whole lot of contemplation.

Why did they go into so much detail about Macbeth’s death and not his rise to power? They gave many clues as to what and how things would take place to precede his death but when they first meet Macbeth to tell him of his advancement of titles and power, they say so little. They could have easily said “Hey you’re going to become king by killing the king…here’s how you do it” or “hey you’re going to become king…but don’t kill him because otherwise you’re going to become one of the greatest literary villains of time. And he’ll die of a tragic accident in like a week anyway”. But seriously why? I can’t really think of anything quite yet; I’ll probably have to reread those sections. Thoughts guys? I mean granted Macbeth did ask specific-ish questions about his impending downfall but he also tried to ask them in the beginning.

My other question concerns Hecate. Was she like pissed off or was it kind of like one of those…”Really guys? Really? Did you have to go and paint on the walls? I gave you crayons and finger paints and lots of paper and you had to go and draw on the walls. Well fine, let’s clean it up and then we can bake cookies.” I know, I know, she wasn’t exactly all June Cleaver, and this isn’t Leave it to Beaver but I don't get a sense of like true anger besides what the witches alude to. I didn’t really get the sense that she was all that upset with them and beyond the fact that she came into scold them what’s her purpose? She comes into tell them to clean up their act and right their wrongs (again an –ish) and nothing else. I really don’t see a role for her. Which makes me wonder if she’s actually a terrifically important character and I’m missing something huge. Help!