AUTHOR'S NOTE:
I wrote this because I read a FanFic like this, asked the author, and wrote my own version. Enjoy!
Things Severus Snape Shouldn't Have Done
1. He shouldn't have died.
Lord Voldemort flicked his wand, and Nagini, his treasured pet, drifted forward in her bubble towards Severus Snape. He let her hover just inches from his face. Snape's face drained of color, knowing he was about to die. His cold, black eyes widened.
"Let me bring him to you, My Lord." Snape pleaded. To his immense surprise, The Dark Lord merely smiled. Snape gave him a puzzled look and tilted his head to the side, examining his master. "What do you wish me to do to her, My Lord?" He asked quietly. Voldemort grinned.
"Take her for a walk."
2. He shouldn't have poured Polyjuice Potion into Barty Crouch Jr.'s mouth.
"The Polyjuice Potion, Severus?" Dumbledore motioned towards Barty Crouch Jr.
Snape glanced at him, folded his arms across his chest, and screwed up his face. "No." He pouted. Dumbledore raised his eyebrows at him, then motioned towards the man in the chair a second time. "No." Snape said again, stamping his foot and turning around to continue his pouting.
Dumbledore sighed. "Minerva, did he forget to take his medication again?"
3. He shouldn't have (in the movie, GoF) walked up to Harry and the Headmaster and given them a puzzled look.
Dumbledore handed Harry the burnt parchment. Harry glanced down at it, read his name, and looked back up at the Headmaster in surprise. Dumbledore nodded, but the baffled expression never left his aged features.
The whole Hall was silent. Everyone turned at the sound of laughter from the Professors' table. Snape was clutching his sides and rolling on the floor. "Him?!?! A Triwizard Champion?!?!? Good one, Albus!!"