Let's say you've been spoken to unkindly. Somebody is abrupt with you. They have been pretty rude.
Focus goes inward, you take it as an insult. You address this personally and begin to feel that burning little pain in your stomach. You find something to eat in order to push the feeling of vulnerability away. Your mood darkens; the chatter in your head has you focus on the worthlessness you feel. After that third bagel you're feeling really down, and somewhat slow.
And the awfulness from the encounter still exists.
Focus goes outward, you get angry. You blame that person their anger, and focus on them and their face, their tone, and the size of their neck to make sure it's small enough so it won't slip out of your hands while you're shaking it repeatedly. You're abrupt, curt, and dismissing. The electrified blood pressure you hold affects engagements with every other person that day, remembering only the face and neck measurements of the person that got upset with you.
Focus goes away, to other thoughts and feelings, to forgiveness and patience. You choose the thoughts you want. You move into wonder what burden this person is shouldering. Maybe it's their life, their challenges, and their perspective that made them so selfish and unkind. You stop for a second, thinking of what their life must be, and say a quick prayer that the rest of their day is better, hopeful that they don't spread their anger to another. You say another quick prayer of gratitude that you didn't go into a previous "neck measurement" mode, which you would have not that long ago had you not practiced meditation, gratitude, prayer.
Your focus creates miracles. It's letting go and placing your feelings into a higher plane-and keeping the practice up to make that happen-that changes the person you've been into the person you want to be.