Those crew only signs?
They usually lead to some where very mundane:
Crew elevator areas
Crew elevators
Crew stairwells
Crew hallways
Now let's compare to the guest areas shall we?
Guests - patterned tile floor, iron detailing, large, elevator Emma telling you what floor you're on, posters of the steakhouse.
Crew - stainless steel box. That's all I have to say about it.
Guests - carpet, nice and wide, paintings on the wall, big landing area
Crew - narrow, metal, white walls, and don't be dropping keys or passes or anything. If you're lucky they'll only fall down a deck or two and not all 12.
Guests - carpet, wide, mailboxes, soothing colours, even the ceiling is painted.
Crew - linoleum floor, white walls, orange doors and funky beige/orange lighting that makes no one look good,
See, not so exciting.