Usability has become a critical quality factor in software systems, and it requires the adoption of a human-centered approach to software development. The inclusion of humans and their social context into the issues to consider throughout development deeply influences software development at large. Waterfall approaches are not feasible, since they are based on eliminating uncertainty from software development. On the contrary, the uncertainty of dealing with human beings, and their social or work context, makes necessary the introduction of uncertainty-based approaches into software development. HCI (Human-Computer Interaction) has a long tradition of dealing with such uncertainty during development, but most current software development practices in industry are not rooted in a human-centered approach. This paper revises the current roots of software development practices, illustrating how their limitations in dealing with uncertainty may be tackled with the adoption of well-known HCI practices.