What flower is this?

Mmm hmm.

Why either? Gay in love also works fine :D

what country is she in and where'd she see it?

edit- is it brazil, central america or parts of mexico?(native) or Eastern USA, Australia, Europe, Africa, China, Japan and New Zealand(invasive weed)

http://telmajr.wordpress.com/2011/11/03/hierba-del-chivo-ageratum-conyzoides/

http://commons.hortipedia.com/wiki/Category:Annuals_and_Biennials(ctrl+f "ageratum" theres several variations that look more or less like that sort of flower so the specific variety may be listed there)

maybe Ageratum houstonianum?
http://www.garten-de.com/foto/de/13627/

http://commons.hortipedia.com/wiki/File:Ageratum_houstonianum_photo_file_103KB.jpg

No, I think maybe Ageratum Conyzoides? http://telmajr.files.wordpress.com/2011/11/ageratum.jpg?w=535&h=401 the placement of the leaves looks more right for this one.

Exactly as the dude above me said, it's pretty difficult to narrow flowers down (there are so many). I mostly know flowers from Asia, this one doesn't look like many from those parts. I really should study up more on it, I love flowers.