How dangerous would it be to cut yourself with an X-Acto?

Like, compared to taking apart a shaving razor and using the blades on that, how severe would the damage be? Could you accidentally kill yourself with a new one? I've used one that had been used multiple times at school before, on wood and sh*t, and it slid across my skin really nicely, really smoothly, and bled nicely.... When I look at them in the store they look so pretty, so beautiful, so tempting, but on the container it says 'caution: extremely sharp' and people have said the same, so, how sharp are they really?

^Yeah, I've got issues, I know......