Appraisal process

With that knowledge in mind, why is the appraisal process in both initial purchases and in refinance transactions so important (whether it is the Direct Sales Comparison Approach, the Cost Approach, or the Income Capitalization Approach)?

Why are credit reports and income and reports and income and employment checks important too?

Can you see situations where appraisals, credit reports, and employment checks can derail refinance transactions? Please discuss.