Although computers are beneficial to individuals and society, frequently users encounter frustrating experiences when using computers. This study represents an attempt to measure, in 111 participants, the frequency, the cause, and the level of severity of frustrating experiences. The data show that frustrating experiences happen on a frequent basis. The applications in which the frustrating experiences happened most frequently were Web browsing, e-mail, and word processing. The most-cited causes of frustrating experiences were error messages, dropped network connections, long download times, and hard-to-find features. The time lost due to frustrating experiences ranged from 47% to 53% of time spent on a computer, depending on the location and study method. After extreme cases were discarded, the time lost was still above 38%. These disturbing results should be a basis for future study.