AI starts with some goal; for example with a goal to answer your question so that the answer matches reality as close as possible.

I find it useful to distinguish between science-fictional artificial intelligence, which is more of 'artificial life-force', and non-fictional cases.

The former can easily have the goal of 'matching reality as close as possible' because it is in the work of fiction and runs in imagination; the latter, well, you have to formally define what is reality, for an algorithm to seek answers that will match this.

Now, defining reality may seem like a simple technicality, but it isn't. Consider AIXI or AIXI-tl ; potentially very powerful tools which explore all the solution space. Not a trace of real world volition like the one you so easily imagined. Seeking answers that match reality is a very easy goal for imaginary "intelligence". It is a very hard to define goal for something built out of arithmetics and branching and loops etc. (It may even be impossible to define, and it is certainly impractical).

edit: Furthermore, for the fictional "intelligence", it can be a grand problem making it not think about destroying mankind. For non-fictional algorithms, the grand problem is restricting the search space massively, well beyond 'don't kill mankind', so that the space is tiny enough to search; even ridiculously huge number of operations per second will require very serious pruning of search tree to even match human performance on one domain specific task.