Jun Xiao presents on the 7 pitfalls of crappy UI design: 1) Designing based on the assumption that "I am the user"; 2) Having "loose buttons" that don't clearly indicate their purpose; 3) Abusing metaphors that don't make logical sense; 4) Prioritizing style over substance by focusing too much on aesthetics; 5) Including too much unnecessary complexity or information; 6) Being too critical of users or providing too much help; 7) Pursuing consistency for its own sake rather than usability. The presentation provides examples to illustrate each pitfall and advocates for user research and usability testing to design interfaces that meet users' actual needs and abilities.