List, in order, I'm sure you can guess which way up !

Not dealing with structural disasters
Bad extensions
Smoking (including smells and dirt)
Swimming Pools
Bad taste exteriors
Artex
UPVC (especially in period properties)
Animals
Bad DIY
Avocado bathroom suites
Nightmare neighbours
Bad layout
Pine
Gigantic sofas, oversized furniture and clutter
Overgrown gardens
Fake features
Dizzy decor
Cheap laminate flooring
Themed rooms
Carpet in the bathroom