Kabooooom

I thought I know so much about it, but this time I realised I was wrong.
I thought I had it tightly in my hand, but really it was out of reach.
I thought I had all the calculation right, but I made the most careless mistake.
I thought I am happy with the way it ended, but I actually hated it was so short.

Wonder what is IT? hahaha. I'ma leave you all in suspension. Oh yeah I am evil.