Poet Gary Snyder writes in Just One Breath,

Spending time with your own mind is humbling and broadening. One finds that there’s no one in charge, and is reminded that no thought lasts for long.

On a related note, Pema Chodron wrote in Cutting Ties: The Fruits of Solitude:

We can’t kid ourselves: if we never take a break from our busy lives, it’s going to be extremely difficult to tame our minds. This is why it’s recommended to take time every day to meditate. Even short periods of sitting silently with ourselves allows the mind to settle down.