When you are unlucky enough to travel through time and blow up the crucible many times in your favorite Potions Professor's class, do you still have the courage to laugh?
"Professor! You look so good making the potion!"
"Assuming Miss Scarlett's brain isn't filled with splendens roots and slug slime, she'll know better than to pick up her poor wand and stir the potion now..."
"Then may I invite Mr. Snape to the ball with me?"
"..."
If she could have her life over again (of course she has already done so once) Miss Scarlett probably would not risk being caught and used as material to say such a thing.
Shh! The fun begins!