Seth Godin posits that the question "What do you want me to do?" is a danger, and that a great consultant will instead ask "here's what you might need..."
I always think of my mother's career advice which is that your job is to make your boss look good. Expanding that, another part of your job is to make your bosses', customers', and fellow employees' jobs easier. Sometimes that does mean just doing what they need you to do, even if you don't neccessarily think that it's the best way. Teams work by consensus and you cannot be a leader at all times. (Heck, if you are a System Administrator you are probably seldom a leader)
On this other hand, Seth has a good point. We have positions based on technical skills, expertise, and talent. Sometimes what the organization needs is not another "Yes, man" or woman, but a critical thinker who is not afraid to voice their opinion. Especially when that opinion is based on the very expertise for which you were hired in the first place. Employers also need to remember to foster critical thinking among their employees.
If your team's great ideas are being squashes, ignored, or otherwise discouraged, sooner or later your team members will stop telling you what they really think. Is that what you want?