The little spreadsheet overconfidently took on a complex task that was too difficult for it, despite its normal work of valuing simple projects. Spreadsheet errors often arise from overconfidence, where the creator thinks they can handle a more complex problem than they realistically can. There are three main types of spreadsheet errors: mechanical errors from mistyping numbers, logic errors from using the wrong formula, and omission errors by leaving something out. It is important to check work at the end of developing a spreadsheet to reduce errors, as error rates remain consistent even for experienced spreadsheet users. Framing the design carefully and double checking work can help recognize and avoid spreadsheet errors.