I think thats it. There are tons of people who dont like waking up early, and it could be an underlying genetic predisposition. Generally speaking, forcing adults to do something they really dont want to do can create some nasty issues. If an employee isnt a morning person but is expected to show up early regularly, its only a matter of time until something gives. Everyday presents a challenge, and if there is no balance, something starts to accumulate (resentment, anger, jelousy).

At least in school you get a whole summer to recover.

Helidor is referencing the fact that Ryan has / was in the UK, where the school day typically runs 9am -> 3pm or thereabouts (maybe 3.15 / 3.30)

Ah, ok, your choice looks to be in line with your situation.

Regarding younger folks, most people work regular work hours in their 20s, but if you take a poll, I bet plenty of them would prefer other arrangements. In a city like New York, there's plenty to do between the hours of midnight and 4am any night of the week, regardless of one's view of such activities. To paraphrase one founder from a previous job, "it's fun going out Sunday nights. You get to meet the people who don't have a 9-to-5 job." If you think back to college, where people could more or less choose their daytime schedule, most students did not go to sleep before 1am. Being stuck signing up for the 9am class was a major disappointment for people. At the same time, though, lining up your schedule to have every Friday off (which was a rare possibility) was highly prized!

My generalization is that people in their 20s favor flexibility to accomodate nightlife (and fun in general), whereas family folk favor a set reliable schedule structured around their kid's schedule and maximizing time with the significant other.

Bottom line though, employers should sit down with their hires on the first day and ask them what's important to them in their personal life so it can be accommodated.