If you enjoy wit, you'll like these.
  1. "Gladly, but you first."
  2. "So much for that."
  3. "In that case, make it a double."
  4. "And so, Madam, is this."
  5. "So do you." (My favorite)
  6. "I think that would be a good idea."
  7. "Sir, I believe that's the understatement of the century."
    Suggested by @averymonsen
  8. "Asps. Very deadly. *You* go first!"
    Suggested by @ChrisK
  9. You've earned it.
    Suggested by @mokoyfman