Tonight, we plagiarize - I had this conversation, and I still remember it

a) You know, a few months ago, I made a terrible mistake.
b) Really?
a) Yeah.
But I realised something.
And instead of crushing the thought the moment it came I...
I let it hang on and...
Now I know it to be true.
And I'm afraid it's stuck in my head forever.

b) What was the thought?

a) That these are the best days of our lives.
It's a terrible thing to know, but I know it.

b) I don't know about that.

a) Well, yeah. Yeah.
Maybe you'll be lucky.
Maybe you'll have better days, but I doubt it.
We stood on top of the mountain, compadre.
It's a long way do-be-do-be down.