I imagine my dog asks that a LOT. She's a german shephard mix, though, and they're at least rumored to be smart. I get my shoes on, but shut the door behind me - "Why didn't we go for a walk?" I eat breakfast and watch tv - "Why didn't he make me some? He knows I like bacon." She growls, barks, and whines at me when I come home from work and I make a bunch of noise back at her - "Why does he use such bad grammar?" She's very curious.

From all living species that we know of, yes.
No, a question in no way explains our lifestyle and the short answers that would come from it don't either. To explain our current lifestyle analyzing all the factors that lead up to it would burn out the processors on Watson.

If you're asking something more akin to our nature to ask philosophical questions and our inability to answer them to our satisfaction leading to our seemingly pointless lifestyles then I'd say it is a contributing factor. However I'd also say that your assumption that life must come with a point is incorrect. Life does not come pre-packaged with purpose, it's an empty box you need to fill.

I don't think its the asking why that makes us unique I think its more about figuring out why that separates us.

yes

My opinion, Yes

"Why" is a conceptual level that is unique to us so far as we know. It implies an understanding of the concept of causality -- if not always an accurate apprehension of actual causes.

You'd have to tell me why you think our lifestyle is "complex", increasingly so, relative to what, and why that is pointless for me to answer your question. It seems self-evident that the most complex thinkers would have the most complex existence, but that's not inherently a bad thing. Lower life forms have very simple existence but still experience "nature, red in tooth and claw", and worse, have no real understanding of it. It's all blood and terror. At least we've been able, however unevenly, to have more meaningful existences than that. Of course ... lower forms have little to no concept of "meaning" or "purpose", so there's that.

Corvids, octopuses, and other animals with higher intelligence certainly are capable of asking why, as they can understand how things work and adjust their behavior to accommodate it without having to try it first, both to escape and to obtain food from complicated mazes and puzzles.

Young mountain gorillas have even been observed methodically springing snares and traps using branches, so other gorillas won't get caught.
At a certain intelligence level, animals also understand the concept of mirrors and will touch places on their faces where researchers have marked them.

An infant tries to discover causes of why they are experiencing what they are experiencing and this pursuit of causes is never ending. When a child notices something they did not expect, they become very curious, which I think evolves into technological progress predicated on the continued questioning and answers given to "why".

Ultimately then 'why something rather than nothing', for which there is no good answer.

I think asking why in the right places and understanding the answer would have the potential to simplify our lives rather than complicate them. I don't know how unique it is to our species.

Possibly it is related to a sense of self-awareness and 'otherness' . Asking 'WHY?' is a projection, even if it relates to the individual, requiring explanation or justification of anything that is 'not I'

Interesting questions. Why has certainly been unhealthy for us. We should have been asking how?

Well anyone who has kids will dread the "why" word. They seem to go through a phase where they ask "why" to every utterance you make. i think it's good to ask "why" when confronted with the inexplicable. Like Trump becoming President.