Personality will also influence non-AI countries?

[luanmameili[LM]]

Here, only Democratic Crusaders will have such opinion modifier:

Another example, this opinion modifier is only available for Fanatical Befrienders:

Also, it seems that personality will also influence default settings of policies and species rights, as well as auto-generated ship designs.

 

[Quinzal]

While the game doesn't explicitly show you, you are assigned a Personality based on your choices. A list of them can be found here, which I like to reference whenever I get in the mood to do big RP.

You shouldn't need to worry though, as far as I know the 'Our Opinion of Them' thing has no real bearing on gameplay and is just there to let you know what atrocities they've committed that you might want to take into account.

 

[Ryika]

You shouldn't need to worry though, as far as I know the 'Our Opinion of Them' thing has no real bearing on gameplay and is just there to let you know what atrocities they've committed that you might want to take into account.

Correct as far as AI diplomatic decisionmaking is concerned, but there are some minor impacts on gameplay that can potentially create large problems. That's because your relationship status is calculated from the average scores of both empires, and some diplo actions require a certain relationship status.

If you're a metalhead for example, you have -1000 towards any other empire, which pretty much guarantees "hostile relations", which in turn allows you to freely declare rivalries against just about anyone without having to lock an envoy into harming relations for a year - which may sound great, until you realize that the rest of the galaxy can do the same thing to you. I haven't tried, but I'd assume that without the requirement to be actively harming relations, AIs that don't like you will probably gang up on you a lot more.