Jobs-to-be-done (JTBD) is a framework to capture the underlying needs and desires of users and the reason why the decide to use a specific product in a certain situation.
People buy products and services to get a job done.
In that phrase, "job" isn't meant as the employment to earn a living but is a shorthand for whatever a user really seeks to accomplish in a given circumstance. Some jobs could really be big and time-consuming, like accelerating a career. Others might be quick and simple, such as bridging waiting time in a queue.
In JTBD, jobs are strongly connected to circumstances, the environment, the context when a need arises. As a result, the perspective on competing products might change, such as when TikTok, Netflix and traditional TV all compete for the same attention span of consumers. Similarly, car sharing has become a competitor of car dealers because, in most cases, the JTBD is to get from A to B in a convenient manner — not to own a car.
Also, jobs are typically connected with social aspects and emotions as the picture to the right nicely illustrates: yes, there might be a lot of high-tech in the product — but in the end the user wants to have fun and look cool.