By Erin Flaherty (realtor.com) As a real estate agent in upstate New York, I can say with confidence that home sellers are in a great mood these days. And who can blame them? In this seller’s market where homes go fast and for top dollar, many sellers are excited to cash in and make a killing. In many cases, they’ll succeed—yet this wild exuberance can also go overboard. Such bullish optimism could...