The floor holds you up by a rule about electrons

You do not fall through the floor because the Pauli exclusion principle keeps electrons from all occupying the same low-energy state. Electrostatic charge is not the whole story.

Pauli’s principle: no two electrons can sit in the same quantum state. Squeeze atoms together and their electrons would love, energetically, to fall into the lowest orbitals of the combined system. The principle forbids the pile-up. The energy cost of promotion is what you feel as contact.

White dwarfs are the astronomical version. Gravity crushes the star until electron degeneracy pressure, the same refusal, stops the crush. Your shoes and a dead sun are leaning on one prohibition. The scale is the only difference.