I recently did a 7 minute where I walked through a scenario where a For Sale By Owner seller ended up hiring me to do a job he just knew he could do himself. Since we are in a seller's market, he figured all he needed to do was put a sign in the yard and maybe post a few photos online. However, the analysis of the offers we had by exposing the house to the full market showed how he cleared over $40,000 more (even after he paid for my services) than he was willing to accept from a "friend of a friend".
That spreadsheet is one of the best illustrations of the value that a good realtor brought to this client, and I am using it regularly with other sellers.