In reality, this is not the absolute truth.
No matter how one conceals his/her emotions about the way how life treats them, we all get affected.
This does not exclude you and me.
It is normal to react and even stand up against your critics. It is healthy to let go of your thoughts that speak on your favor.
No one else can defend yourself but you. Go ahead and be real!
Reveal your truth and do not apologize for it.
Now after having expressed what you must say, then MOVE ON.
That is the wisest thing to do.
Do not keep returning to the same issue over and over again.
Once you have dealt with it, ignore and yes, keep smiling.
But be sure that before you walk away, you have declared your side of the story.