Conversations with Anou

Anou (short for Anoushka) is my only daughter, aged between 5 and 6.
It is hard to describe her, and I think 'only' is a fitting adjective in this case.
Nonetheless, a number of times, it is quite refreshing to talk to her.
Today, I was in a mental turmoil, and I was preoccupied and in foul mood for the whole day, and I began to realize towards the evening that she was not taking it so well.
So I talked to her:

Milan: Anou, I am the one doing 'Wain Wain' the whole day today, isn't it? (I say Wain Wain to describe her being cranky).
Anou: (signs bodily that she concurs).
Milan: Do you know why? Because I was not feeling nice today.
Anou: Why?
Milan: Umm... (momentarily overwhelmed when I tried to recall the source of my distress)
Milan: ... I am trying to explain, but I am finding it so hard to explain.
Anou: Why?
Milan: Because-
Anou: No. You said it's hard-Why? Why so hard?
Milan: ...
Anou: Just say 'I don't know'.

I sputtered out a laughter, surprised and tongue-tied with the simplicity of the answer.