In a House of Lies, by Ian Rankin

I read Ian Rankin's latest, "In A House of Lies." The story is very complicated and sometimes hard to follow.  But I don't read Rankin for the story.  I read him for the characters, and the regulars are all here: Rebus, Siobhan, Malcom and Cafferty.  They have come to be like good friends.  I did notice a tic in the writing that grated.  Over and over again, one character "watched [another character] nod."  Once I start noticing it I seem to see it everywhere.