Let's say you pencil-dive into the black hole. At first, you fall down with mostly constant gravity acting on your entire body.
But there is some distance between your head and foot, so your foot's gravity calculation begins to yield higher forces than your head as you get closer to the singularity.
As this effect plays out, you get elongated, and the distance from head-to-toe increases even more, magnifying the effect, which in turn magnifies the effect more and more until you're spaghettified.
> We are talking about forces stronger than strong nuclear force, but somehow affecting body locally.
It wouldn't be a black hole if it didn't outmuscle whatever gets close enough.
Well, "how long it takes" is kind of the whole point though...
Few are rushing to die...
When Mars One launched their competition to become the first people to go to Mars, explicitly on a one-way trip, more than 200,000 people expressed an interest. Only 4000 or so actually paid the competition entrance fee though. (https://en.wikipedia.org/wiki/Mars_One#Astronaut_selection)