Answer:
It happens when something has been cut with H2O.
A house with two occupants, sometimes one, rarely three. Break the walls, eat the boarders, then throw away me.
If you break me, I do not stop working. If you touch me, I may be snared. If you lose me, nothing will matter.
A harvest sown and reaped on the same day in an unplowed field. Which increases without growing, remains whole though it is eaten within and without. Is useless and yet the staple of nations.
Stealthy as a shadow in the dead of night, cunning but affectionate if given a bite. Never owned but often loved. At my sport considered cruel, but that's because you never know me at all.
What is so fragile that saying its name breaks it?