Eruptions!

Consider a volcano and the changes it goes through over its lifetime.

I was always the silent one
Never grizzled or grumbled.
My siblings were never short
of something to say.
Blowing off steam.
I was always the onlooker,
like the passive smoker.
I watched you splutter and spew,
Envying your ability to vent your anger
Whilst I stood in your shadows
for my turn to bathe
in the limelight,
you fumed ferociously.
My calm demeanour maligned
My fiery spirit
VOLCANIC.