"No Big Deal" highlighted Anne's growth and newfound happiness in Amphibia. Marcy, as was evidential in her journal, must have been torn up inside with guilt for stranding them, no matter how many times she tried to justify her actions. So to hear what she did helped Anne be "finally her" would have been awesome to hear. What she did was worth it right? She used this line of reasoning in True Colors: "Look how much you've grown. Look at Sprig, I gave you this, I GAVE YOU EVERYTHING." She helped Anne find her happiness, her worth, what true friendships look like, but at what cost? Loss of trust, stripping her friends away from their lives, etc...Marcy gave them everything, but also took everything.