In our mind, we think about good and bad things.

Give yourself rest and peace of mind by thinking more about things that are good, honorable and right.

Philippians 4:8 (KJV) – finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report: if there be any virtue, and if there be any praise, think on these things.