Stars usually mean your project is useful to someone, so they are indeed nice to see. They're also an endorsement of people who use a project and are apparently

Stars usually mean your project is useful to someone, so they are indeed nice to see. They're also an endorsement of people who use a project and are apparently happy, so the project is more likely to do what it says and do it well. These metrics aren't usually a problem until people attempt to game the system like it's done on platforms like youtube, but I'm not aware of this happening on github (at least not often).