Optimism means refusing to let fear monopolize imagination.

Fear is vivid and repetitive, and left alone it will occupy the whole of your imaginative capacity. Optimism, practically speaking, is the act of insisting that other pictures also get airtime. It is a matter of allocation rather than of feeling positive.

When a fearful scenario keeps replaying, deliberately construct an equally detailed version where things go reasonably. Give it the same attention. You are not lying to yourself; you are balancing the ledger.