jumping the gun

abrupt hasty impetuous instinctive offhand passionate spontaneous violent

ad-lib automatic careless devil-may-care emotional extemporaneous flaky gone off deep end headlong hot-and-cold intuitive involuntary 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

hasty ill-considered untimely

half-baked half-cocked inopportune overhasty precipitate previous too soon

backward careful cautious delayed late mature overdue prepared slow