I mean, some people really like comprehensive acknowledgments! And if you’re putting a bunch of them in, it can be intimidating to worry that you’ve left someone out and they’re going to read it and they’re going to see all these other people named and they’re going to confront you like oh so I wasn’t good enough for you huh but . . . hey, if the worst happens and you do forget someone, you could always mail them a personalized signed copy. 🙂
Look at other people’s acknowledgments. Many to most do not have a whole lot of names, or they might just have a dedication. Look at the acknowledgments of people who might have thanked YOU. Look at the acknowledgments of people you’ll definitely be thanking. Look through notes and saved e-mails. And if you’re not at this point yet but you’re terrified you’ll forget people. . . .
Start keeping lists.
(Yes, I have two pages’ worth of acknowledgments, why do you ask?)