I found $150 on exiting the toilets, and handed it to the receptionist. She sent out an email to the whole office, and the owner was found.
From where I come from, if you lose something, and someone else finds it, and returns it, you owe him 10% of the value.
Well, this guy did not even thank me.
Although I know it's illegal and partly immoral, next time I find money in the office, I'm even more tempted to keep it.
The vibe here from the OP's responses isn't positive at all. Could be something to do with the OP's personality in the office that could deter the cash owner from showing their sincere gratitude.
Returning the cash should be closure of the situation. Anything that comes after should not be an expectation, anywhere in the world.