Sadness; depression.
It yells,
"Move on!"

"Don't be weak!"

"Aren't you stronger than this?"

As it keeps kicking you in the gut.

But, I will fight back.

I will punch sadness directly in its face and I will laugh.
"I have moved on!"

Punch.

"I'm not weak anymore!"

Kick.

And suddenly, it'll be gone.