She fails by not keeping the characterization or clothing consistent.
Panel 1: We're at the sandbox in the park. As he plays with a toy steam shovel, Mike tells Lawrence that there's gotta be a reason boys and girls are different. It should be noted that a little girl with her hair in a ponytail is filling a bucket with sand. Also, Mike and Lawrence aren't wearing what they were yesterday/a few minutes ago.
Panel 2: As the girl with the ponytail walks away, Lawrence tells Mike that he asked his mom but she wouldn't tell him.
Panel 3: As we see another little girl push a toy carriage, Lawrence surmises that they must have different decorations.
Summary: This is a more-or-less realistic depiction of how regular little kids who are more or less six talk about things that confuse them so I like it; what I don't like is that it's embedded in new-ruins that have them acting like they're roughly eleven.
ETA: The latest banner shows us the lighter side of neglecting your pets.