Hacking a computer is a lot like riding a bicycle.
Let’s say, for instance, that you give a kid a 10-speed bike. If the kid’s stupid, he’ll hop on and try pedaling like they do on TV. He might fall off because he doesn’t know how to ride it. Eventually, he gets the hang of it, but notices it’s really, really hard to go up hills. If he’s really stupid, he’ll keep pushing harder on the pedals, maybe wear himself out, maybe give up saying “well, they just don’t want me to use this stupid thing! They should just make it work!” But if he’s smart, he’ll overcome his fear of possibly damaging the bike from making changes from the default settings and will start moving the gear levers to see what happens. And it’s through that defiant act of making a small change to notice any big benefits that he eventually learns his bicycle and finds it his most useful tool for getting where he wants to go.
That is hacking.