gone off deep end

abrupt hasty impetuous instinctive offhand passionate spontaneous violent

ad-lib automatic careless devil-may-care emotional extemporaneous flaky headlong hot-and-cold intuitive involuntary jumping the gun mad precipitate quick rash sudden swift unconsidered unexpected unmeditated unpredictable unpremeditated unprompted up-and-down winging it

calm deliberate planned sensible

cautious considering heedful premeditative thoughtful wise