Stupid questions

Of all the questions that are meaningless and impossible to answer, I would guess that most of them start with why? Try conversing with a four year old if you disagree.
"Why is that picture up there?"
"Because it looks better there than on the floor."
"Why?"
"Because we can see it better there."
"Why?"
"Because the light shines on it better."
Why?
"It just does -ok!"
"Why?"
You know what I mean, and it isn't just children that ask that question. How often are we asked for our opinions only to have that awful follow up - "Why?"
Most of the time the Why question is impossible to answer fully without incurring the inevitable repeat. Even fundamentals like "Why did you make Chilli again?"
"Because i wanted to."
"Why? we had it yesterday."
It's probably because that's all i could find or all i could be bothered to do but I have no idea really.
From a purely scientific point of view, asking why is rarely productive. "Why are there rainbows?" for example can produce all sorts of stupid answers that offer fairies, leprechauns or God as perpetrators. It is much more sensible to ask What is a rainbow. That can be answered reasonably lucidly by most intelligent people, but there is usually some dimwit at the back who will follow your explanation with a "But Why?"

Why did I start this??????