My beef is that I was in a game being double teamed by the Yor (they're evil, so I suppose it's only natural to attack in the first place) and the Altarians (I don't know why these guys don't like me, but they hate me consistently in every game). I allied with the Drath, who then promptly ignored my "threats" that they should help me to stop the Altarians. 3 turns later, the Altarians and the Drath allied, but the Altarians were still knocking me around while the Drath looked the other way!
I also hate it when a race says "That race is getting too powerful, we must stop them before it's too late". I figure, ok cool, you have a point. So I then suggest "Hey, why don't we attack that guy together?" I then get the snippy response of "Why would we do that?" (or something similar).
I think this needs to be addressed in a future patch, since the AI just acts like a bunch of d**ks sometimes. In good ol' Moo 2, when the Bulrathi started agressing me, my allies the Trilarians were always the first ones to pipe up and say "Yo brotha, let's kill those fools". They were my own little "Mr. T" ally.