Does this happen to anyone else?

[ecosopher]

Now that I've got my plot and outline worked out, I keep thinking of awesome sentences I would use in the story.  Not just sentences by themselves, but whole paragraphs that kind of just evolve... and I want to write them down, but I feel like it would be cheating.  And I'm scared if I don't write them down, I'll lose them forever!*

Is it just me?!!

*A very good possibility, considering I'm suffering from Pregnant Brain right now.