Why sellers sell for below appraised value?

[Devin Bost]

I'm learning how to fix & flip homes, and I've noticed cases when properties are listed on the MLS for below the appraised value of the property (or so they claim). In the current market, it seems that appraisers are much more conservative about their estimates than they once were. I can understand that a highly motivated seller might be willing to discount the price below (perhaps significantly below) the value set by an appraisal, but I don't have enough experience to understand how often this is really the reason.

Are there any hidden "gotchas" to beware of when investigating a property that has a listing price that is significantly below the appraised value? 

[Chris Mason]

I'm guessing you are conflating tax assessor value with appraised value, since that's what you can see publicly.

Property tax assessments have little to do with market value. It's just a gov't number. The gov't also thinks pizza is a serving of vegetable since it has tomato sauce. Not credible.