AH! It's about how Elly can't cope with Lizzie!
That's because it's the single panel blast from the past that has Elly with head in hands moaning "One cookie! I only gave her one cookie!" because she's overwhelmed by the mess Lizzie made with it. A mess, I might add, that a less sensitive soul would be able to clean in about five minutes. Not Elly, though. This is a tragedy to bleak to contemplate, not a minor chore she'd do and forget an hour later.