Here's why:

* Hydrogen bonds require hydrogen: Hydrogen bonds are a type of intermolecular interaction that occurs between a hydrogen atom covalently bonded to a highly electronegative atom (like oxygen, nitrogen, or fluorine) and an electron pair on another electronegative atom. NF₃ does not have any hydrogen atoms.

* Nitrogen's electronegativity: While nitrogen is electronegative, it is not as electronegative as oxygen or fluorine. This means that the nitrogen-fluorine bonds in NF₃ are polar, but not polar enough to create strong enough partial positive charges on the fluorine atoms to participate in hydrogen bonding.

In summary: NF₃ has a polar molecular structure, but it lacks the essential hydrogen atoms needed for hydrogen bond formation.