Kristen Stewart is one tough cookie and her smile, an ever tougher one to crack. When should we expect teeth, when do we deserve a stern, barely-there grin and what makes her beam in delight? Your guess is as good as ours. But at least when KStew does smile (or tries to), we can try to make sense of how it makes us feel.
Below: A handy guide to KStew's cryptic smiles.
Infographic by Jan Diehm for The Huffington Post.