There are two categories of performance errors that engineers must worry about. The first are visceral issues: those that actually stop the experience altogether and abruptly. These include crashes, which are fairly easy to diagnose and stop, and things like memory issues, CPU pegging, and too many concurrent network calls, which are more difficult.
To put it simply, we love mobile. Mobile is the center of our lives and will continue to be the center. Three simple examples of why: