Fiona shares an office with her ex$-$husband. Her share of the rent and utilities is $$625$ per month. She is considering moving to a home office which she will not have to share with anyone. The home office will not cost her anything as far as extra rent or utilities. Recently, you ran into Fiona at the gym and she tells you that she has moved into her home office. Fiona is as rational as any other person. As an economics major, you rightly conclude that

Fiona figures that the additional benefit of having her own office $($as opposed to sharing$)$ is at least $$625.$

Fiona figures that the benefit of having her own office $($as opposed to sharing$)$ is zero, since she is no longer paying rent and utilities.

Fiona did not have a choice; her ex$-$husband was a jerk.

The cost of having one's own space outweighs the benefits.