My same two answers are always Fight Club and The Godfather

I’m a huge HHGTTG fan, even have the green planet as a tattoo, but the Dirk Gently books were definitely a bit more irreverent imo.

Where the Red Fern Grows

Man’s Search for Meaning, read it every four or five years.

I honestly don’t think I’ll even read it if it ever comes out. After the third book, I just found it to get less interesting through four and five. Plus it’s been over a decade since I’ve read the series and I’m unwilling to read it all again.