One of the unfortunate perks (not!) of being sensitive is that words that might not have carried that much weight or were said jokingly might hit you harder than intended.
It changes you- the knowledge that it hurt you more than intended and you subsequently trying to hide it. You start pretending to be someone you are not, you paste that smile on your face, permanently etched for all to see. They joke and you laugh along, all the while smiling while it slowly kills you inside.
Gradually, the world splits into two kinds of people. One that forever sees you as the happy go lucky person that you endeavour to be, the constant source of reason and joy in their lives.
And then there is these other kind of people. They see the walls that you have built so high around yourself. And they call you cold and heartless. There is a certain trend to them. Some look on with pity, some with censure and some with something pertaining to hero-worship for the stony facade you show them.
There are times, times when the feelings threaten to brim over that wall you built, you just barely manage to reign it all in, and carve a smile on your face.