I remember being stressed for undergraduate science laboratories, unsure whether I understood the protocol sufficiently and worried that I was going to “mess up” in the lab. With this in mind, I thought about what I could do to help ease my students' anxiety in a new third year laboratory course I was developing. The answer was an online decision tree that guided students through laboratory procedures, which I named LaboraTREEs. Students would do the module before coming to lab, making mistakes online where they were not in sight of others.