Honestly, a personal OR professional failure essay could be just fine if you are able to clearly define the problem and explain the growth that came out of recognizing and rectifying that problem. The only thing I think that’s a bit boring is when one writes yet another essay talking about some academic or research struggles since we as medical students have ALL experienced at least some degree of hardship in these areas. However, if you are able to tell a story that is unique to you so much so that it keeps me reading then the scenario shouldn’t matter as much theoretically. But also keep in mind that telling a failure story outside of academia is also going to be a good way to make a good impression because you look like a multi-dimensional applicant who has some real life experience to bring to the table.