so depended on the views of people and cultures,everybody like to see beautiful things and everyone wants to look pretty,making oneself happy is a good thing because you put out a positive vibe in doing so to the surroundings.so what ever interest you can be made obsessive by oneself if gone to the extremes.
it is not vain to make yourself happy by doing so.
also remembering too much of something is bad enough.
we live for a short period of time, well human mind change all all the time.
well the answer to your question is not always people think negative of beauty.
majority in the world love to see pretty and charming people.