You never know what someone is going through that’s why we need to be sensitive enough to everyone. Everyone’s facing a battle we know nothing about 
Have you watched the movie called “Wonder” on Netflix? That’s one of the lessons you can learn from it. Such an inspirational one 
Ah, I’ve watched it already! That’s true you should always be sensitive enough because you really know what someone is going through. One can always be smiling but is hurting deep inside.
Just be kind always, to everyone. We can never really tell, someone may seem jolly on the outside but really sad on the inside, just be sensitive to whatever they are going through.