We don't (or didn't) get to have them
Long enough

We don't (or didn't)
Appreciate them enough

We don't (or didn't) listen
We think we've heard enough

We think we don't need them
We didn't need them enough

We think we'll never miss them
We'll miss them more than enough

We're only given one apiece
That should be enough

We don't tell them we love them
(at least not often enough)

We'll remember them forever
…And that still won't be enough…

David Whalen

http://www.poemhunter.com/poem/moms-forever-s-not-enough/