Good to see you here again, Khrysso.

A really interesting question and I see it similar like you - it's not absolutely necessary, but perhaps it's something like a catalyst (remember chemistry? ;-) ). As a catalyst is pretty much the opposite of an inhibitor the comparison becomes even more interesting:
We get inhibited by the society (education, social environment etc.) what makes us inhibited in many ways - we don't see and don't feel the wonders of nature anymore that we were so much intrigued by when we were little children ...
And to break out of this prison (or tearing down the wall - as Pink Floyd painted pretty much the same thing in their album) is usually impossible to do without pain ... only in our "comfortably numb" comfort zone we feel secure and cozy. But at times we feel that we miss something, but often we stop thinking further - as even this may hurt already - and no human likes to be hurt. - So we have basically just two choices to get free : either voluntarily (accepting quite some pain, but in little pieces) or forcefully by some event that we didn't choose ourselves.
For me it was the latter one - and for all that I know personally too.

So the quoted sentence "Something comes along to open us up, and it's always terrible." describes this painful way perfectly.

Perhaps it's just that our brain is designed this way, that, when something really terrible and painful happens to us, that it focuses on the main living functions - on the "essential" things in life - and this (hopefully seldom experience) has a uniquely huge potential for us to recognize these essential things and value them from then on much higher than all these many neat but actually useless things we were used to treat as sooo important. ... We wake up ... literally.