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• Dysfunctional floor plans: Someone needed more bedroom space so they added on, but it messed up the traffic flow. It was much worse than just having to walk through one bedroom to get to another. “You had to walk from the living room through a bedroom to get to the kitchen,” said Hicks.
• Too few bathrooms: It’s a hard sale when the house has many more bedrooms than baths. Five full bedrooms with a single bath, for instance, makes the morning traffic jam very tough. An example is where there are three bedrooms on the second floor and two on the third, and a single bath located in the basement.
• Garage Conversions: Needing more space, homeowners often make new bedrooms out of old garages. But thoughtless conversions ruin the curb appeal, with the new residential wing still looking like the old garage.
• Big kitchen – no living room: Some homeowners have hobbies or interests that they devote major floor space to — at the expense of everything else.
• Bedrooms with no closets: This can evolve in a couple of ways: The previous owner could have removed closets to increase the bedroom’s floor space or added bedrooms to a house where there was too little room for closets.
• Really bad colors: An awful color scheme may turn off homebuyers so much that they are blind to the home’s other virtues.
• Overgrown Vegetation: Everybody loves trees and shrubs, but let it get too lush and it turns into a problem.
• Missing parts: Neglected houses can have issues such as an outside basement entrance to nowhere — except basement…essentially just a big open pit.

For more:  http://money.cnn.com/2011/01/24/real_estate/houses_of_horrors/