1) For most of history, we could only do work during daylight. 2) Agricultural work specifically wants early light - there's a lot of things you can't do in bright sunlight because it stresses plants.
It's definitely around for a while - the whole "the early bird" thing dates back to at least the 1600's. Aristotle was mumbling about getting up early as well. ("Rising before daylight is also to be commended; it is a healthy habit, and gives more time for the management of the household as well as for liberal studies."[1])
Personally, I'm more a fan of Diogenes ;)
So, likely it's considered good because it maximizes "productive" time.
[1] Economics, Book1, section 1345a: http://www.perseus.tufts.edu/hopper/text?doc=Perseus:abo:tlg...
- One component of the popular concept of "laziness" is staying in bed for much longer than you need for sleep.
- It's not symmetric: going to bed early is not popularly associated with laziness because going to bed is an active decision (you have to change your state from up to in bed). In contrast, staying in bed is passive.
- "laziness" is considered morally bad
- Being a morning person involves waking up early and is therefore thought, rightly or wrongly, to be evidence of "not laziness".