I tried to like them, but too often the main character is a total asshole and nobody calls him on it. Also, the author is a little too enthusiastic about too-clever narrative tricks like having the story told forward and backwards in alternating chapters.

But mostly I got annoyed at the protagonists naval gazing and being only concerned with their immediate problems (that they usually created) when there was a giant interesting universe shoved into the background.

I also tried reading one of his non-culture novels (Transition), and it had exactly the same problem of a main character that just seems to be killing time until the novel ends.

My favorite characters in the Culture books are the AIs, not the humans they are keeping around as pets.