What do I do the moment I catch myself in a bad thought?

You notice with every single thought type, the continual answer is always the same. You have to cut it off as soon as you realize that you're engaging in it. There's nothing to be gained from it. The only thing that is gained is when we get rid of these weak ways of thinking and we learn how to live by faith in the present moment, trusting in God's mercy. And the only way to do that is to not get distracted, to not be swept away, to not get into imagination, fantasy, the past, the future, what's happening now, what could happen, what about this conversation, all these different things. Why did this happen this way and it didn't happen that way? The only way to do it, and to really be a mentally strong man, is to sit in exactly the circumstances that you're in and keep all of your focus on Christ. Notice that when Peter was on the waves of the sea, he focused on Christ and was able to walk. But when he got distracted and the wind came and these things, he began to sink. This is the same thing that happens to us mentally as men. In order for us to stay above the waves of life, we must be dialed in with our focus on Jesus Christ. And our words must continually be the proclamation of our heart: Lord Jesus Christ, have mercy on me. We say that not as if we are afraid of Christ. We say that as a man who is about to go below the waters. Have mercy on me. Grab me, pull me back up, and help me to walk on the waves of life. If we engage life in this manner, with this type of mental fortitude, we will be unshakable as men, because all of our hope and our trust and our power comes from the Lord Jesus Christ and not ourselves.