Why is Minecraft so cloudy?

Answer 1

Depends if you are talking about minecraft Classic or Minecraft full version.

Minecraft Classic:

Pressing the F key on your keyboard will turn on/off fog.

This fog is useful for players with slower computers which are affected by lag while playing Minecraft Classic.

Pressing F will toggle the intensity of the fog as well as turn it on/off.

Minecraft Full:

Fog exists for the same reason in the full version of Minecraft.

To disable it or modify the intensity, either press F while holding F3 or in the game options, set Render Distance to "Far".

Lag is caused in Minecraft while maps are rendering. For people with slower computers or computers with outdated graphics cards, the lag can be a little too much. This is why Mojang, the creators of Minecraft, introduced fog. By turning on fog you are reducing the amount of rendering that Minecraft has to do when loading a map. Sure, it lowers your vision a little, but as a result it does reduce, if not completely remove, lagging issues for slower computers.