Animations often rely on timing functions to dictate how transitions occur. Historically, Bézier curves have been the go-to solution, offering options like ease-in and ease-out. However, they have limitations, particularly when trying to achieve effects like springs and bounces. Traditionally, developers turned to JavaScript libraries for these effects, but this approach can lead to performance issues, especially since most JavaScript animations execute on the main thread. The introduction of the `linear()` timing function in modern CSS simplifies the creation of such animations. Instead of using complex curves, `linear()` allows users to specify points on a Cartesian plane, which are connected by straight lines. For instance, an animation can be defined using a series of numbers that represent the transition's progress. A well-crafted `linear()` function can produce convincing spring animations by adjusting the number of points used in the transition. Tools like the Linear() Easing Generator and Easing Wizard help automate the process of generating these point sets, making it easier for developers to create smooth animations without manually calculating values. Despite its advantages, the `linear()` function is still time-based, which can limit its flexibility compared to physics-based animations. CSS transitions require a fixed duration, while physical animations typically rely on properties like stiffness and damping. This disconnect can lead to awkward implementations, especially when trying to model behaviors that should theoretically oscillate indefinitely. Another challenge is handling interrupts; web animations can be disrupted by various user interactions, complicating the expected behavior of the transition. The article highlights these limitations while also providing practical tools and methods for creating more dynamic animations using CSS.