Hm, well... she has never had much patience, or has been precisely an explosion of love with anyone... but definitely, and far above other things that annoy her, touch her hair without permission is the worst thing you can do to disturb the lady. Really, it's a bad idea...
Unless you want to lose your balls. Literally. In this case, go ahead... enjoy her anger in the form of fists, kicks, insults or any other type of aggression that the lady can think of.