If you feel like you are doing the best job possible but not liking the people around you (maybe your boss or coworker is taking all the credit or you have a bad supervisor who is not letting you grow), it may be time for a switch in jobs. But that doesn't mean a switch in careers - it could just be a job in a different industry / sector or for a competitor, etc. Everybody has a brand that they are building so you want to not only look at your job / career but also how others around you perceive you - if people around you are impacting that brand then you do need to take a close look at who you surround yourself with.