What does it mean when a female co worker usually smiles at you anytime they see you?

[yeahimadude]

Honestly im not sure what I could've done that caused her to smile at me, but honestly im not complaining about it. Frankly it brightens my day everytime I see her smile at me.
But our interactions don't really go anywhere though we usually just walk by eachother, she doesn't approach me to talk unless its work related. So I figure its best that way

[Nikki1989]

Newsflash: Some people are just friendly. Chill out.

[LC75LC71]

She's a nice person. Probably friendly to many, which is pretty awesome in itself.

[slatyb]

She's crushing on you. Ask her to lunch or whatever.

[In_Trance]

Nothing