The Culture/YMMV

"Ulver Siech: "It looks like a dildo!" Churt Lyne: "That's appropriate. Armed, it can fuck solar systems.""
 * Boring Invincible Hero: A common view of the Culture, in universe and out. Whilst the Culture is easily one of the most powerful meta-civs in the galaxy (possibly others), it is the first to admit that the Sublimed have them down each time. So they don't bother messing with them. And the Culture only stay "invincible" because there are people, drones, and Minds, who are capable of doing anything necessary to protect it's continued existence and interests.
 * Fridge Brilliance: The game theory concept of the "iterated prisoner's dilemma" states that the logically optimum course of action when dealing with a totally unknown entity is to lead off with a minor but benign gesture and then to tailor your responses to mirror the other entity's replies re: cooperation or noncooperation. Now think back to the plot of Excession, and you will realize this is exactly what the Excession was doing. The GSV Sleeper Service even Lampshades this briefly.
 * Freud Was Right: Played with in Excession with dROU Frank Exchange of Views.


 * Mary Suetopia: One thing that makes Banks such a great writer is how he averts this: he is the first to admit that the Culture is the "ideal society" in which he dreams to live, and he is also the first to show how imperfect it is. Specifically the possibility for complete, mind numbing boredom, and the repeated claim (by both citizens and outsiders) that The Culture in fact cannot stand cultures different to its own, and so seeks to "sanitize" the rest of the galaxy. Staving off this boredom and giving purpose to the Culture's existence may be Contact's real function. Also, the utopian nature of the Culture is presented as entirely a function of their post-scarcity economics. When they find anything that actually is scarce, they are only too ready to compete over it.  Ultimately, Banks simply acknowledges that even the Culture can't be all things to all people; it's just as close as the author can make it, while still being mindful of the reader.
 * Tear Jerker: Quite a few of these have taken place throughout the series. One of the most notable would be, for example,   Use of Weapons In Matter there was also the