Utterance from the unimpressed

• "It was fine, I guess"
• Jaded interjection popularized by "The Simpsons"
• "I'm lukewarm"
• "Color me unimpressed"
• Response from someone who's heard it all before
• "It's not great, but not terrible either"
• Word of indifference
• "I've felt better"
• "I could take it or leave it"

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
expression of apathy or indifference, by 2003 (perhaps from 1992).