What do people expect, when it breaks one of the few "rules" that English orthography has. First off, its as the possessive form of the third person singular personal pronoun is an innovation. It used to be his, but its won out sometime in the later 16th century. Second off, most of the other possessive forms of pronouns are irregular, except for one's. Why? About the only rationalization I can come up with, it is to purposely trip people up and have them making mistakes. Third off, I really don't think the apostrophe adds much to the mix. English must be one of a set of a few languages which hasn't had a spelling reform, ever. Fourth off, why are so-called abbreviations which are actually contractions, use the apostrophe? D'r Jekyll and M'r Hyde. Now that I'd like to see.

Ceci n'est pas un seing.