It certainly takes balance! If the person giving direction is well informed or your Superior then you should listen and ask questions if you don't understand. Don't be afraid to step in every so often and give your ideas and values. A good friend, boss, or coworker would be happy to have someones ideas and values to make things better all around and in some cases some of those ideas and values may make money for a business.
It's the way your present your ideas and values. If you are persistent and demanding your words will flow away on the wind, but if you are quiet in demeanor, firm and have your ideas clear or even written on paper and it's well thought out then your ideas will probably be listened too. As far as values you know right from wrong and if you think something is wrong then make a point (in a good tone and not aggressive) that you disagree and be willing to give a good reason why. When there is a problem try to give a resolution if you can.
If you are in any job and feel that you are being 'excused' or under estimated with your ideas and values then move on and find a business that would appreciate your enthusiasm.