How and why do the witches upset Macbeth?
In Scene One of Act Four (of the play Macbeth), Macbeth gets very angry at the witches. He approaches the witches calling them hags and demanding more information about the prophecy they showed him earlier in the play (Act One, Scene Three).
Macbeth, demanding the witches tell him more about his future, chooses to hear the voices of their bosses.The witches ask Macbeth
Say, if thou'dst rather hear it from our mouths, / Or from our masters?
To which Macbeth replies
Call 'em,; let me see 'em.
Macbeth, therefore, has come to the witches because he is fearful of everything which has happened since the initial prophecy and fears for his life. He is forceful with the witches because he knows that the answer which they will, hopefully, give him will allow his concerns to be settled.
After the witches disappear, Macbeth does not seem to have been completely consoled. He curses the witches and damns those who trust them. (Ironic given the fact that Macbeth has trusted them in the past and continues to trust in the apparitions brought forth by the witches.)