Bootstrap's popularity as a frontend web development framework is easy to understand. It provides a palette of user-friendly, cross-browser tested solutions for most standard UI conventions. Its ready-made, community-tested combination of HTML markup, CSS styles, and JavaScript behaviors greatly speeds up the task of developing a frontend web interface, and it yields a pleasing result out of the gate. With the fundamental elements quickly in place, we can customize the design on top of a solid foundation.

But not all that is popular, efficient, and effective is good. Too often, a handy tool can generate and reinforce bad habits; not so with Bootstrap, at least not necessarily so. Those who have watched it from the beginning know that its first release and early updates have occasionally favored pragmatic efficiency over best practices. The fact is that some best practices, right from semantic markup to mobile-first design to performance-optimized assets, require extra time and effort to implement.