I read somewhere that human has the ability to store a lot more garbage thoughts than useful one. Maybe because the garbage are much more fun than anything else. Although your definition of garbage and mine can be different, but I digress there. Your brain tend to mark your mental calendar and retrieve them, unconciously when you encounter certain sight, smell, touch, hear something. Sometimes certain words and act would definitely bring back floods of thoughts too. Sometimes, these flashes of thoughts will translate into words.
And those words, the way they are spoken, can be painful.
Usually, seconds when the meaning of those words have sunk in, you either react to it by saying something hurtful back or in most cases, you will not respond until certain time.
Will you forget? Will you ponder?