People have some control of their thoughts.
A friend of mine reported that he used to be negative, cranky, unhappy. So he chose to think of good things.
When he found himself thinking unhappy thoughts, he would interrupt them with happy thoughts. Thus, over time, he became an upbeat person.
In an earlier incarnation of this website, we had a poster named
Alonzo Fyfe. He came up with a morality called
desire utilitarianism. In this theory, some desires are better (more moral) than others.
Suppose ten white racists want to beat up a black man. This will make the victim unhappy, but it will please the rapists. A naive criticism of utilitarianism would say that -- according to utilitarianism -- the racists should go ahead and beat their victim, because that will make ten people happy and only one person unhappy.
Fyfe would say, I believe, that the ten racists are in the wrong for wanting to hurt someone. They should adjust their desires. They should learn to take pleasure in kindness rather than cruelty. It is by learning better desires that they can make the world a happier place.
I haven't studied Fyfe's theory well enough to be a qualified spokesman for it, but I believe it to be the best version of utilitarianism, and thus the best theory of morality.
Desire utilitarianism depends entirely on our ability to have some control of our thoughts.
Sometimes I get an unpleasant earworm, a song I keep remembering. Sometimes I'll interrupt that loop by deliberately thinking about another, less-unpleasant, song. Often enough this works; I'll have started a new earworm, one that I like. This may be a crude example of someone controlling his own thoughts, but it is an example.
In the movie
Moonstruck, John Cage's character tells Cher's character that he loves her. She responds, "Snap out of it!" Not an unreasonable request, I think, but nonsensical if you don't think people have some say in their own thoughts.
Current events distress me, so I choose to avoid most news sources. I avoid the distress by choosing not to think about current events.