Guys, what do you think of a attractive girl that rarely smiles?

But she has a nice but shy personality? She's very kind and polite but keeps to herself and doesn't interact with anyone unless they interact with her.

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by the way this is how she acts at work. She's all business and doesn't try to befriend anyone at work. But she's a reliable and hard worker. If you ask her to do something she'll do it and put effort into doing it.
Guys, what do you think of a attractive girl that rarely smiles?
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