It's called familiarity.
Not very pleasant but true. When Alex, the girl who won the normal big brother a few years back entered the house, I thought, how ugly I thought she was, but after a while, I couldn't see it anymore. And it's funny you mention this about Alicia, because I thought the same would happen with her. Not that I think Alicia is ugly but that surgeon of hers has a lot to answer for.