Redneck Bear

Hi, and I'm sorry for such a lame question, but ... why the heck keep Sylvester and Felix doing what Maeve tells them to? Are they only afraid for their jobs? Or so much scared of her? Or why? Perhaps I missed something as I'm not a native English speaker - but I really don't know ... I can understand Felix being unable to "kill" Maeve but apart from that I'm quite clueless.