How to pick out a head of lettuce?

PlunderBunneh

Just over six years ago, when my then-fiance shared our decision to marry with his parents, his mother turned to me with an aghast expression and said "You? Do you even know how to pick out a head of lettuce?"
My reply "Uhh...Find the one that's not brown?"

Now these days, I know her better, and since I do enjoy a good back-and-forth, I mention this lettuce event often. Usually finding an excuse to go to the grocery with her, and respectfully ask for her advice on what lettuce looks best, since she is, afterall, the expert.

Anyhow, we're traveling to see her this weekend, and I was hoping all of my lovely interweb friends could give me a very descriptive guide to picking out a head of lettuce (to show her I've been researching, even if technically you're researching for me), or other such ways to torment this sweet woman.

And don't worry, she trolls me too. That woman had me 99% convinced that it was an old family tradition to bathe newborns in the oil of anchovies. She even sent me tins of anchovies as a baby shower gift.