I don't think they like me

I had finished my game (won via culture) and was playing with world builder giving myself a whole stack of nukes - haven't used them in an actual game, wanted to see the graphic. Anyway, I proceeded to nuke a few other civs and then looked at the diplomatic screen - I don't think they liked me.

I am still wondering why the American's were only -1.

Maybe you didn't manage to hit the Americans with any of them

I only bombed rome, japan and russia. The others are angry because I bombed their friend - boo hoo!

The Americans probably were at war with or hated the ones you bombed.