Good songs vs Bad songs

Upon hearing "What I've done" once again last Thursday, I tried to analyse its meaning, which I had never bothered to, on the bus as I had nothing to do.

In this farewell
There’s no blood
There’s no Alibi
‘Cause I’ve Drawn Regret
For the Truth Of a Thousand Lies

So let Mercy Come
And Wash Away
What I’ve Done

I’ve Faced myself
To Cross out what I’ve Become
Erase Myself
And let Go of What I’ve done

Put to rest
What you Thought of Me
Well I Cleaned this Slate
With the Hands of Uncertainty

So let Mercy Come
And Wash Away
What I’ve Done

For What I’ve Done
I’ll start again
And whatever pain may come
To day this ends
I’m Forgiving What I’ve Done

What I’ve Done
Forgiving What I’ve Done

One problem about this song, which I also find with quite a number of other songs nowadays is the choice of content and the vagueness of it. For example, in "What I've done", the entire song revolves around the regret of murdering someone, but there is nothing mentioning the reason for murder. This might not be a very big problem, but to me, it would not be any better against songs like "I don't love you", which clearly mentions how someone left his lover due to ill-treatment.

Other not-so-good lyrics includes The Reason. The person keeps on mentioning "the reason" to change but never said what he had done wrong or how he had hurt someone else.