Bathroom Etiquette

Okay, would someone please tell me what the hell the problem is with women not flushing the frigging toilet in public bathrooms?! There is nothing more disgusting to me than walking into the bathroom at my office (not a restaurant or in a mall but in a place of business for pete's sake!) and finding someone else's refuse floating about in the can!

Do people do this in their own homes?! I do not, repeat, do not, get this, so if anyone has some insight please god share your wisdom!

And hey - the job is still going great by the way! They seem to like me lots but still no word if my contract will be extended after the end of September, so still crossing bits in hope!