The public library is an American institution. There are public libraries around the world, but the American definition is really unique.
The purpose of our library is to provide equitable access to resources and materials. The operative word here is "equitable". Our policies are designed to make sure that resources purchased with public funds are shared effortlessly.
Yet it seems there is a sense of entitlement that makes it possible for some to believe that they should be exempted from policies and rules. It seems that there is little concern that because they do not have their materials back on time, someone else is deprived of access and use.
And we, the librarians, worry about interactions and negative experiences in the library and about the patron always being right. How "right" is it to let a few essentially take advantage of the rest? How to explain to others that wish to use library resources that they are gone?
Honor the system. Return materials on time. Honor the basic code of ethics so that all have equal access to the library's resources. Hold sacred to the notions of fairness, reason, and justice. Rules for access and use of library materials apply to all, not just some.