If you can quickly replace it with another illusion of happiness that you consider real happiness, then you’d better know what you’re doing.
Otherwise, your righteous cause will spread unhappiness and possibly misery.
Truth alone isn’t some magical fix-it-all. I’m going to die. You’re going to die. We’re all going to die. That’s the truth. Do I tell it to someone who just fell in love and is on top of the world? I _could_ – it would be truth. But what point does that serve?
No, if you’re going to apply truth, it must be applied carefully.
There’s no reason for truth to wreck someone’s happiness and if you’re wrecking happiness with your truths, however much you feel/think/believe it is THE TRUTH, then you’re doing the world a disservice and should really investigate your intentions.