We're like the Smart Phones, except for the "Smart" it's still under discussion =))
We charge all night, to discharge all day
If we didn't charge all night, we won't be able to discharge next day.
Sometimes we decide to optimize the battery saving so it can withstand the whole day with acceptable charge and we sacrifice using 3G, games or even the music player and more amazing features... those features which made us buy the smart phone in the first place.