Be careful not to panic into taking action or saying something, until you carefully think it over in your mind. The fruit of acting impulsively is regret. When you act impulsively, you might make irreparable mistakes.
It is especially important not to make major life changes when you are guided by emotions. If you are emotionally excited (either in the positive or negative), wait until you calm down before taking action.
Sources: Shaarey Kedushah 1:6; Rabbi Zelig Pliskin’s Gateway to Happiness, p.261