Letters I should send:

Dear Second Child,
Getting you down for a nap is ... exhausting.  Having you sneak out of your room into mine, climb INTO Millaker's pack-n-play, and waking her up is not my definition of "napping."  To add insult to injury you were rubbing Decitin on her head when I came in saying, "Look, Mommy! Lotion!"  Dear, dear, dear child.  Just. Nap.
Sincerely,
Your tired Mama.

Dear Power of Moms,
I love you.  I love your resources.  I love the new skills I'm learning as a podcast editor.  I love the articles, podcasts, deliberate mothering ideas etc.  I love the new ideas and inspiration you send my way.  Thank you, thank you, thank you...
Sincerely,
A grateful mom.

Dear Four-Year-Old Son,
You are brilliant.  If you get too much smarter, I'll swap you places and you can be the thinker and planner for the day.  Please stop out-thinking my disciplining and distraction ideas.  You should know, I love when your eyes sparkle when Dad gets home and how you don't consider anything but wrestling and the "tickle game" as playing.  EVERY night you cry that you haven't gotten to play with Dad very much even though he's spent the last hour with you.  You are a funny kid.
Love,
Your out-witted mother.

Dear, Dear Millaker,
How DO you smile so much?  I want to pick up this habit.  Everyone, and I mean EVERYONE, is drawn to your smile.  When you're not smiling you are sticking your tongue out.  I think I'll pass on that habit.  Thank you for brightening my day.
Sincerely,
Your smiler-in-training mother.

Dear Cardboard box,
Who knew you could provide SO MANY HOURS of entertainment (and arguing) for young children.  I would keep you around were you not bent, hashed, ripped, and teetering on the side of the source of too much arguing. 
Till the next Amazon shipment arrives,
A grateful mother of entertained children.