Nothing outside yourself can cause any trouble.

Nothing comes from outside your mind. Usually we think of our mind as receiving impressions and experiences from outside, but that is not a true understanding of our mind. The true understanding is that the mind includes everything; when you think something comes from outside it means only that something appears in your mind. Nothing outside yourself can cause any trouble. You yourself make the waves in your mind. If you leave your mind as it is, it will become calm. This mind is called big mind.

– Shunryu Suzuki

from the book "Zen Mind, Beginner's Mind"