Mobile application is an emerging area of interest, growing exponentially each year. Among the many mobile applications, only a few remain competitive. The success of a mobile application depends on its context of use and user experience (UX). In a pilot study, we tried to find and review user interface (UI) and UX problems by analysing user sentiments towards apps based on their text reviews. In addition to this, to fully understand the cause of the UI and UX problems, the Thinking-Aloud method was used. Text reviews cannot be directly used for UI/UX problems and most of the problems were related to the planning-stage of the interaction cycle. Our approach may help app developers/designers to focus on particular UI/UX problems of applications.