Resolving software bugs is arguably the most important task of a software developer. Only by adequate software testing can developers find bugs in the system and fix these errors. However, with one fix often comes another bug, and the linear process becomes a cycle. It's possible that these seemingly new bugs weren't caught during the pre-release phase.
Research shows that a well-equipped software developer can catch 95 percent of known bugs prior to a code's release. The catch rate has remained somewhat stagnant over the past two decades despite advancements in software development. While a bug-free release is achievable, it has proven to be as rare as a blue moon.
Then again, bugs aren't necessarily all bad. Anything made by human hands is bound to have its set of problems, after all. Constant updates enable software to enhance its functionality over time, in hopes of achieving a bug-free state. As long as software developers offer sufficient support post-release, bugs will hardly be a bother for a well-equipped developer.
That's how software today works: release Version 1.0, receive feedback, design new features, release Version 1.1, and repeat. Over time, the developer learns valuable lessons and reduces the risk of earlier bugs reoccurring.