Messy models destroy trust instantly.

What's your worst modeling story you ever dealt with? It would be fair to say that I have a recurring financial modeling nightmare where students or customers send me their Excel model. And what I do is I have an analogy of how you sometimes need to untangle that Christmas tree light series that, you know, looks like a big ball of wires and looks like a tumbleweed. That's exactly what I think when I get some of these Excels. Probably one of the worst I have dealt with is this customer sends me an urgent model for a loan application. It's the perfect example of the anti- anti-modeler. It had all of the worst practices: no inputs, all cells hard values everywhere, no formulas, each scenario was a different sheet. It was a mess. No units, no text, and those horrible data islands all around, links to external workbooks. As usual, it was urgent, so I was better off throwing it away and start from scratch, which I did, and eventually their loan was approved. But unfortunately, it's very common to get models like that.