silly

Matt was spray painting some things the other day, and the fumes were strong. We were laughing about how many brain cells he was killing.
Several days later, Colesy says to Shelby: You know the other day when Daddy was killing our brain cells? I think it is sorta a good thing.
This is where my ears perked up! I wanted to hear the good in dead brain cells!
She continued: We get more hair.

??? Huh?!

Oh! I then remembered how several days before, I had told them that their hair came from dead cells......

So, in Colesy's head, that all made sense.