I suddenly thought of a book earlier. I can't remember a great deal about it and now it's driving me nuts. It was an American book in the Jay McInerney or Bret Easton Ellis vein, though not one of them I don't think.
The central character was a middle-aged man who was having a mid-life crisis. He worked in an advertising agency or similar; his boss was a woman; most of his colleagues were younger and more successful than him; one of them died. There was something about a totem pole in a backyard that may have belonged to the dead colleague. There is a bit where he locks himself in the car. There was something very significant about a particular office chair. It was a relatively recent book - last 10 years or so.
I've probably forgotten all the significant plot points and only remembered isolated images, but I'd be really grateful if someone with a less selective memory than mine can tell me what it was! There's no point in my going home and looking for it as I'm 99% sure I got it from the library.
I remember it was a Richard & Judy bookclub choice from a few years ago. I read it but it didn't make a huge impression on me. I didn't love it, but I did remember enough of it to be able to identify it from your description