This is because it can give you information about what will happen once a particular setting gets turned off.
Using the cooperation of several mod developers, Shaders Mod provides graphical changes to shadows, weather, light, and map drawing.
I've had games such as minecraft and had to wait a year or more for some bugs to be fixed.
Check all Optifine Features.
Optifine allows the player to adjust the greeneries on the side of the dirt block with the Better Grass adjustment, and snow can also be adjusted just as much with the Better Snow.
With GLSL Shaders Mod, you may find yourself taking notice at natural aspects in the game that would otherwise be overlooked.