That's generalizing a bit. As a "hackelor" myself, I can tell you I don't function well at all in small spaces and can't productively live anywhere that lacks copious empty space. I live in a three-bedroom apartment with one other person, expressly because we couldn't find a two-bedroom place with enough open space.
Yes, empty space is important. One personal trick I've found for doing with less actual space is to sit next to a window so that almost half my peripheral vision is into a much larger area. This is especially helpful if that window also has long lines of sight available.
