How's about this for a crazy premise: man pays organisation to kill him painlessly if he should have progressive fatal disease or accident rendering him comatose. Changes his mind, but the organisation won't let him. Organisation is ruthlessly efficient at killing assorted passers-by but hopelessly inefficient at killing the man. Man meets previously unknown son. Son gets fatal disease and goes into hiding. Man tries to find him, while at the same time avoiding the paid assassins.
Well it does sound crazy, and it is. The shark is definitely jumped more than once in this book, Kill Me by Stephen White. Yet it doesn't matter. The book does its job at drawing in the reader — it almost lost me after the unappealing first chapter, but because I've enjoyed all White's previous books, I persevered. And although the plot did indeed become more ludicrous as the book progressed, I was carried along by the persuasiveness and immediacy.
This book is a departure for White in that he writes from the point of view of one of Alan Gregory's clients, so we don't see the action through Gregory's sometimes rather prim, even smug, perspective. For my part, I would have enjoyed the book without the "thriller" element, or if the thriller element were inevitable, would have preferred there to be a twist or two (I can think of a couple) rather than for the plot to be quite so predictable. But in the end I didn't mind, because White can write (and, to touch on a contemporary theme, and as he says himself in the end notes, his editor can edit).
I can't write anything distinctive or profound here about why people (eg me) like crime fiction so much, as many academics have gone before me and can write with far more insight than I. After all, a book like Kill Me is well insulated from the believable world. But for my small part, I would suggest that a book centred on the therapists' encounter with the client (think early Jonathan Kellerman for the epitome), including the challenge of how to deal with a known fatal condition (as here), enables the reader to travel to places that aren't too comfortable in this hard old unforgiving world of reality. The fact that it is unbelievable that this character would take out such a "death insurance" policy, or that an organisation would exist to fulfil it, doesn't matter. The fact that the character sets the policy to kick in at a very preliminary stage of illness is also neither here nor there. The strange rules that the organisation has, for example not killing any clients in their homes in case it looks suspicious, but being quite happy to kill via sniper on a scaffolding in a blocked under-mountain tunnel with a car set on fire as a smoke cover — totally bonkers. Yet none of this matters, because these plot devices allow the reader to explore some uncomfortable questions. Under what circumstances is choosing death better than living a life? Put a family in the mix, how does that change things? What factors would make such decisions change? These are the underlying issues addressed in "Kill Me", and I guess they are the reason why the book "works" despite its plot.