Picture above mostly posted for comic effect, but really it's a matter of courtesy. I could light up whole town and it would benefit my visibility tremendously but I'm not the only person on the road and have to consider how my action affect those around me.
Yes, I can see better with all the lights on, but if all the drivers around me are blinded by glare or have to squint or avert their eyes then it makes for a far more dangerous situation than having dim headlights.
Assuming reasonable height vehicles, the low beams should be aimed so that the top edge of the light pattern is 2 to 3 inches below the centerline of the headlamp at 25 feet. Tonight, go find a wall, measure the height of your headlights, put some masking tape on the wall, back up 25 feet, and start adjusting.
The rest of the driving world will thank you.