Some sellers are delusional and think their house is special and that it will sell for more than they list, even expect it.

There have been times where I made an offer and the seller countered and based on their contingencies, I got the vibe that they were going to be an asshole through closing.

One seller even threatened to sue even though I was fully within my rights to walk away. My response to my agent was "tell them to serve me papers."

Never heard from them again.