Quarreling with parents, giving up on that girl, getting into a relationship with that soulmate, having one night stand with that close friend, saying those inappropriate things at the wrong time, making that rash mistake, not studying enough for that paper, and I can go on listing this the whole night (and it's gonna include me blogging this instead of sleeping now)
But what really matters is learning from these lessons and prevent them from happening isn't it? Not exactly, some things will still happen all the same even if we go back in time knowing the consequence. Because seriously, you only live once...
