Corrections: Most but not all government forms in Canada use yyyy-mm-dd format, which is a positive change. But indeed we are used to living in a mishmash of American, European, and ISO influences. Americans might get angry if you don't use mm/dd/yy format; I'm not aware of them being attached to dd/mm/yy.
My american users get very angry when they see a date that isn't in dd/mm/yy format.