An Olympic Athlete Trainer says this:
There are four negative feelings or thoughts that produce toxic chemicals in the brain. They are Hate, Greed, Fear, and Jealousy. To get his athletes to do better, he says that they must change these to positive feelings and thoughts — Love, Generosity, Courage, and Praise.
He claims that service to others is one of the best ways to move into this healthy context; and he has found that doing this has proven to be effective in producing the winning edge.
This is indeed an interesting discovery! Thoughts produce chemicals, and positive thoughts produce positive chemicals. Of course, there is a time for sorrow and vexation, but they must not dominate, or they will infect.
So we would do well to ponder this and to reflect on what our own thoughts are. Granted, we cannot control our feelings. We may have a feeling of sadness come upon us. We didn't seek to feel sad, but it is nevertheless how we are feeling. Likewise, we cannot control a feeling of urgency, or frantic-ness, or frustration, or anger. These feeling come unbidden.
But . . . and this is the key! . . . we CAN control our thoughts. Our thoughts can change our feelings. Thoughts produce chemicals. Consciously entertaining a thought of Love can absolutely affect your feelings toward another person. Deciding to think thoughts of praise about another person, of God, or of particular circumstances will — they WILL — begin changes in your feelings.