That's not even true, though. If you are kidnapped and then tortured, you are not remotely in control of your own happiness, just to take the most obvious extreme answer. Even for more mundane situations, people can be trapped in terrible situations, where cruel people have power over them. If you are working at a minimum wage job with bills coming seemingly every day and which you only overcome by working 18 hour days before collapsing exhausted and doing it all again in the morning, there is very little you can do about it. Now if one of the supervisors at one of your jobs is a petty tyrant who makes you miserable, what choice do you have that would increase your happiness?

I see what the quote is trying to say, as a call to action to change your own life, but it simply isn't true. It also fails the false wisdom reversal test, in that a quote saying "You have no true control over your own happiness; therefore, you must accept your lot in life with all the grace you can muster" sounds just as deep and helpful.