I am not sure they make any difference. I have one game where an alien race has practically ceased to exist. They only have one plague ridden planet with no population and they still won't surrender. I mostly use the different moods for RP just in case it makes a difference. Even with human players. I don't know that you can see what mood a message is in but if other people know how to they can figure out my messages tone I guess.
Name := Normal Asteroids
Number of Poss Abilities := 0
Name := Normal Storm
Number of Poss Abilities := 4
Ability 1 Chance := 250
Ability 1 Type := Sector - Damage
Ability 1 Descr := Turbulence causes damage to space vehicles.
Ability 1 Val 1 := 200
Ability 1 Val 2 := 1
Name := Unstable Warp Point
Number of Poss Abilities := 1
Ability 1 Chance := 1000
Ability 1 Type := Warp Point - Turbulence
Ability 1 Descr := Strong gravitic fields causes damage to ships.
Ability 1 Val 1 := 200
Ability 1 Val 2 := 0