I hate how today "Because I really want to do it" is no longer a valid reason to do things. There always has to be some ulterior motive that's at least as big, if not bigger than what you're trying to achieve.
And the main reason I hate it is because it artificially moderates people - those with big dreams that they want to do "just because" stop and ponder and, sometimes, eventually give up on them because there's no bigger "why" than "why the fuck not?" - AND it makes people feel bad for stopping and doing, for a while, absolutely jack-diddly-shit nothing because they felt like it.
To me, the question "Why?" is a complete concept killer. We should ALWAYS be asking "Why not?" or some variant. From small things like actions ("Why do you want to build robots?" shouldn't be answered with "Well I want to make the world a better place and I think robotics is a good place to start" if it doesn't need to be; "I like robots so I'm gonna make 'em" should be a good answer - likewise, "Why aren't you doing anything?" shouldn't needlessly be answered with "I needed a break" when all people mean to say is "I got nothing important to do right now and I feel like doing nothing right now") to medium-scale things ("Why do you want to lose so much weight?") to deep, fundamental things ("Why does quantum mechanics work?").
I feel that we would be more productive by asking "Why not?". Because the question "Why" implies that there has to be a reason. "Why?" is the question of minimum effort - because "Why" implies that if you don't have a tangible goal that makes you do that, there's no point in it. "Why not?" makes us do things by removing the base necessity of needing a purpose for doing things - yet, by asking why the opposite of what's being done or of what will be done isn't being done, we get to think about the repercussions and consequences of our actions, keeping us reasonable. "Why not go to space?" "The reasons why not are inconsequential so I see no reason not to." VS "Why not speed on the highway?" "There's people and curves - I could get myself, or others, hurt".
And it applies to science too - you know how there's a saying "The exception makes the rule"? I'm pretty sure we could get some VERY interesting insight in all fields if, instead of asking "Why does it behave like that?" we ask "Why DOESN'T it/shouldn't it/can't it behave like that?" and, from that reasoning, either find that it DOES infact behave like that, or find a mathematical model of why it doesn't and close down that path of reasoning until something else is discovered that may put it at stake (or until someone decides to have a closer look at it)
At least that's my opinion. For humanity to secure a future for itself, it must start asking "Why not?"