Do you know what to say to an ungrateful person?

When you're young and you have just entered market place, most of the times you have to start small. Starting small refers to the act of starting something from the bottom, and from there on maybe build your way up. In business, starting small can be considered a good strategy because you become able to experience new things when risks are still low. That way, you can take the chance to become more experienced before trying out something big.

But the problem with some people is that as soon as they leave college, they want to be at the highest level of an organization, a company. It becomes a problem because at the moment they realize it is not that easy they're more likely to give up the job before a chance to grow. Suppose for example a friend of yours has been looking for a job for a long time to no great avail. You then tell him you can get him a job at the company you work for and he seems to be very excited about it.

However, when he finds out the job you found him is not the job of his dreams, he gives up. You think he's very ungrateful for feeling doubt about something good that has been offered to him. So you say: I know it is not the job of your dreams but it pays good money. I'd be inclined not to look a gift horse in the mouth if I were you.

When you tell someone not to look a gift horse in the mouth, you're criticizing him for refusing to take something that has been offered.

Fonte: http://idioms.thefreedictionary.com/look+a+gift+horse+in+the+mouth