A social media app might fail due to a lack of features, poor user experience, and technical issues such as glitches and errors. The user feedback indicates that the app is limited in terms of what it can do, with users only able to add friends and view their posts. Additionally, the user is not able to post more than two photos at a time, and the app does not include any videos for users to post or watch. The controls of the app are also confusing, and the process of adding friends is on a separate page, making it even more difficult to use. All of these issues can lead to a poor user experience, which can lead to users abandoning the app.