Why does Banquo not trust the Witches?

Banquo is skeptical of the Witches’ intentions and remains unconvinced of the Witches’ prophecy. Banquo warns Macbeth that “instruments of darkness” often tell half-truths “to win us to our harm” (1.3.125–126). While the Witches have prophesied great futures for both Macbeth and Banquo, Banquo is less inspired and intrigued than Macbeth and would rather leave the matter safely alone.