The word passion is defined as the strong and barely controllable emotion. Which is what we believe Romeo has for Juliet and Juliet for Romeo. Although there is haste involved, the excessive speed or urgency of movement or action. They definitely 100% are in a hurry to get married after only knowing each other for 3 days.
Juliet drank the poison the night it was given to her without taking a day to think about the reality of what she was doing.
Romeo's decision to kill himself after finding out that Juliet was "dead" because he didn't get the letter in time explaining what actually happened. If he would have waited and thought about what he was going to do, maybe they could have still been together well and alive.
"Don't let your emotions make your decisions"