Background: The anticipation of anesthesia and surgery is the source of fear and anxiety in millions of patients worldwide. Although patients' fear and anxiety are recognized, more knowledge is needed to address patient responses and needs. Understanding the needs of the patients are important, and asking patients directly is the first step towards addressing these needs. This again might help reducing medications such as anesthetics and postoperative pain relief. The aim of this study protocol is to describe how we will investigate what matters to patients on the day of surgery, as well as their degree-of-worry and surgical fear. Methods: Using a convergent mixed methods design with equal weighting of the qualitative and quantitative data strand we take advantage of the international “What Matters To You” Day on June 6, 2024 to conduct a flash mob study. We will approach perioperative departments around Denmark to participate and eligible patients arriving to the perioperative department for surgery will be invited to participate. Consenting patients are asked to complete a survey in three parts regarding (1) what matters to you, (2) degree-of-worry, and (3) surgical fear. We will use qualitative analysis for the first part and descriptive statistics for second and third parts. The data strands will be analyzed separately followed by integrated analysis and joint displays.