All good points! I have the same tendency to pick up and drop books based on mood and what’s going on in my life. I recently just picked back up Sapolsky’s https://en.wikipedia.org/wiki/A_Primate%27s_Memoir which I had abandoned years ago after reading roughly the first half. Picking it back up, I enjoyed it so thoroughly I became a bit avid in my reading and finished the rest of the book in a week or so (which is rather fast paced for me).
I like the metaphor of reading being like listening to the radio. I often feel guilty for dropping books or not powering through (there are many, many books I have read the first quarter or so of and shelved with the intention to finish another time). Probably healthier to have a more free and less “driven” mindset towards reading books.
Sometimes I drop a book because I enjoy it so much I don’t want it to end, I want it to always be there and to relish it later. This is a bit silly - there are always other books, but I also will forget the plot over time and eventually the book will be enough like new that I can enjoy re-reading it.