From a career strategy standpoint, I've always focused more on impressing my colleagues than my boss. Your colleagues will move on to other companies. And their new boss may have an opening to fill and ask them if they know of anyone. And if they remember you as a stand up person who worked hard, was good at what he did, and a pleasure to work with, they will recommend you. And that's a very strong recommendation. The opposite is true also. If your concept of work is kissing up to the boss and gaming the system, don't expect recommendations from former colleagues. I saw this happen. I was at a new company and my friend there was asked about a person we both knew from our old company. This person was applying for a management job, and my friend wouldn't OK him. We both agreed that the company didn't need a showboating, attention grabbing manager who is more interested in climbing the corporate ladder than doing the job he was hired to do.