Sure, discursive thinking is useful, but doing it as an unconscious habit is problematic. That's what meditation seeks to help address, for example, and cease the endless 'chatter in your skull'. Like, when you're thirsty and see a bottle of water on the counter, why think to yourself "I'm thirsty. There's some water there I can drink." Who are you talking to? You know you are thirsty, and you know you can drink it. The discursive thinking to echo it to yourself is just a bad, clutter-some habit.