Many times, developers that come from others platforms such as; web or desktop, take for granted that developing for mobile is the same, when it is not. The reality is that it is a quite different environment. Usually, they tend to bring the same techniques, patterns, and libraries, that they were accustomed to using back in the old platform. Ignoring that those practices are detrimental to user’s experience and the general image that everybody has about Android. Attendances will learn or review, what variables are vital and we must be taken in due consideration if we want to be good citizens in the Android town, like; CPU, memory, network, storage and the bitter reality that low-end devices are still in many user’s pockets. And how the proper use of those factors translate to user’s satisfaction and remuneration. Android is a unique platform, a developer without a proper understanding of what is the right mindset about developing apps is like. It is just a recipe for disaster. Performance matters! This talk is inspired by the medium article of Chet Haase and mix of my daily experiences.