"I could go either way"

• "Two thumbs sideways"
• One’s not moved border up
• "Big whoop"
• "Does nothing for me"
• 'So what?'
• "I'm not excited by this"
• “Who cares”
• "I'm not overwhelmed"
• Slangy way to say "whatever"

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