Distant Worlds:
You can set how 'friendly' your own government/AI is overall. But... the alien AI can still piss off your AI.
Setting tendency to go to war: Low
Your AI will almost never be the one to declare war. Actually, they never have from my experience. Its different for the alien AI though, they use default settings... but... you can spend credits and do stuff to placate them.
Also, if you have ships on automated... they may decide to attack outposts within your territory if your AI hates the trespassing outpost's owner enough... which will increasingly sour relations if left unchecked for years... You also take a big hit to reputation. (The Guardians... damn em...)
Mind you, friendly treaties like giving mining rights, refueling rights, rare resource trade and free trade that you ggrant, it can be nullified by your AI, due to your AI not liking the alien AI.
Though, you can set the tendency/willingness to break treaties to low... but hate is still a strong factor.
EDIT: For clarification, this is if you have both Peace Diplomacy and War Diplomacy at fully automated.
Each race has a 'I naturally like you/I naturally hate you' factor with the other races. For example, the Insectoids and Humanoids do not naturally get along.
Some races are war-like by default and will probably pick a fight with you if they dislike you. There are other factors which can cause war, like being near enough another kingdom that they would want your stuff or if you are massively bigger/superior(envy).
And yea, each race has unique victory conditions too, so yea.
I've been playing on Legends, I'm pretty sure they added the automated options for the base game too, but meh, I'm not checking.
If you are turned off by the cartoonish race pictures, you could try the extended 38 races mod on the matrix forums, changes all the pictures. And there are the individual ones that change the pictures too and what-not.