The idea that in such a chaotic world, we should look for the tiny things that bring about joy. However, I disagree with this! This sounds like education system PR junk! It is said by school people. Therapists. Even my parents. It was useless for me.
Quantity over positivity. Denying reality is toxic. Big beats small most of the time! If the negativity is more than the positivity, the negativity wins every time. And the multiplicative effect of negativity (darwinism), humans were wired to be more fearful of danger than good!
When you don't talk about the big problem at all... This is the even bigger concern about "little joys". Problems need to be solved, by nature, so this implies manipulation or a social mask...
Forcing people to be grateful... Forcing people to list out happy moments... the rule is that: if it's forced, it's not natural. Forcing a crying baby into smiling immediately is futile. I cannot rely on unnatural testimonials. And then people may actually hate it when they are happy! This could be how pessimism is born! Worse of all, it implies that not being joyful is wrong because it does not suit the asker's needs, which just makes it even sadder!
Let the communicative partner talk about how they really feel, about the "big picture". That way, a more "pragmatic" and "honest" image is born. After all, little joys just seem artificial and worse if it becomes a learned habit (as you will end up asking people around the world about it, causing it to spread, as you think it is the correct thing to do, asking about people's joys may not necessarily bring about joy!)