I am somewhat uncertain about whether people who are kidnapped and tortured are in control of their happiness. I know there are at least a few people who've been in those situations or similar ones, like the Holocaust, who report that they retained some control over their own thoughts and perspective and this was a source of comfort and strength to them. I think it is possible that people who are tortured are in control of their own happiness, but they generally tend to make the choice to break.

One example that comes up in discussions on this is medical depression, which I have. From introspection, it feels like it is both true that I have control over my happiness and that it is not true that I have control over my happiness. I can recall occasions on which I have consciously chosen to lie in bed and be unhappy, and I can also recall occasions on which I have consciously chosen to uproot myself from misery. However, there are also occasions where I've attempted to do this but failed. I think the answer to our dilemma lies in compatibilism: we are in control in the sense that what happens inside our heads matters, but not in the sense that we can transcend our physical limitations and become omnipotent.

Also, it was listed as an instrumental rationality quote.

All of that said, I downvoted the original comment. While I think it is a defensible point of view, I want rationality quotes that are insightful and compelling, not ones that regurgitate conventional wisdom which some people will automatically believe while others will not.