Why can some runways only be used from one end? Is there any reason for why some runways can only be landed and taken off from one end and not the other, even though there aren't any obstructions (mountains, etc.) and apparently can be used from both ends?
Even if there are no physical obstacles visible - the airspace structure can be somewhat more difficult and one runway direction might run into other reserved airspace. Or just go over noise-sensitive neighborhoods...