with blowing my top. IMO letting off steam is a controlled process by which I can regain equilibrium. Blowing my top is the tempertantrum that is an explosive process where everything and everyone is in imminent danger of immolation. I've been known to do that also. Just never on the keyboard.
btw, thanks for the spelling correction. Phrase was used frequently while living in der Vaterland. Never did see it spelt, just spoken.