The new land of "WHY"

Just recently, Andrin has discovered a new word: WHY?
Our discussions are tinted by his questions about why something happened, why we did something, why we went somewhere, why he was to do something ...

This discussion transpired yesterday:

Andrin and Papi went to soccer in the morning and then to the local fly shop (yes, Papi was able to get another fly fishing rod because of his job!). Mami took the opportunity to take a long walk with Bigna bundled up in the Baby Bjorn and got some applesauce for Andrin at the store. Papi and Andrin were just getting out of the car when Mami got back as well.
Andrin was carrying the fly rod under his arms and stopped in his tracks when he saw Mami walking up to the house as well.

Andrin: Mami, why come from that way?
Mami: I went for a walk with Bigna and then to the store to buy some apple sauce.
Andrin: You went for a walk, why?
Mami: Because I felt like it.
Andrin: Did you take Bigna with you, why?
Mami: Yes, we do not leave her home alone like we do not leave you home alone as well.
Andrin: Mama, you went to the store, why?
...

Andrin really seemed to ponder on the fact that I went to the grocery store with Bigna since he brought it up at night again. I finally asked him if he actually wanted to go to the store as well, he just noded his head.