Everywhere I've worked (for the most part) you had to be there between 8-5 (roughly). You just couldn't leave early even if you came in early. I know it's not like that everywhere. My current job I am almost always the last one here by 5 and it's just hard to break the habit that I have to be here until closing time.
Exceptions were made if you made arrangements with management but usually only people with families or college/schooling got any leeway.
I work 7:00 - 3:30 and go home early on Fridays.
wait, how can you go home earlier than 3h30? :)
In reality I sleep 8+ hours and laugh at those who "boast" at how little sleep, or how many hours they work at the expense of other valuable things in their life (family, socializing etc.)
Also, a lot of these comments are about the mid-afternoon/post lunch nap. Honestly I'd prefer to get home to my family a bit earlier, than take a mid day siesta and have to come home later in the evening.
Getting up early and clocking out early are especially tempting given how little daylight we have (Northeast US) this time of year.