Concerns about patient safety have prompted studies of adverse surgical events (ASEs), but descriptive classification of errors and malpractice claims have overshadowed qualitative investigations into the processes that lead to expert errors and their solutions. We studied consultant surgeon's perspectives on how and why events occurred through semi-structured interviews about general and specific events. The sample contained heterogeneous cross-section of ages, gender and specialists, with >2 years consultant status and working within a 25-mile radius. Overarching findings included (1) pressures to work harder, faster and beyond capability within a blaming culture; (2) optimism bias from over-confidence and complacency; and (3) multiple pressures to ‘finish’ an operation or list, resulting in completion bias. Seven high order themes were identified on the healthcare system, adverse event types, contributing factors, emotions, cognitive processes, error detection, and strategies, solutions and barriers. The process of classifying event types guided solution selection, and the decision about whether to formally report it. How serious consequences were for patients and their temporal effects, defined an adversity continuum. Minor events arose routinely i.e. technical discrepancies, side-effects. More problematic were sub-optimal outcomes and avoidable events. Despite their expertise, consultants were vulnerable to unavoidable, uncontrollable events which were major concerns. Most serious were near-misses, errors and mistakes. However, major errors did not inevitably lead to a catastrophe and minor errors could be extremely serious. A ‘cascade’ of minor events exacerbated by negative emotions can precipitate major events, and interception methods need investigation. Consultants felt powerless and helpless to change environmental, organisational and systemic problems; new communication and action channels are desirable. Confidence building in team leadership would promote ‘flatter’ hierarchies, facilitating appropriate warnings. Although implementing the WHO Checklist averts important problems, social, environmental and organisational contributing factors are largely overlooked here and in existing models.