The responsibility of a contractor involves more than just knowing how to do the job, the technical aspect of it ; it also involves the ability to work as a team and KNOWING ONE'S POSITION.
One must know the chain of command / communication in executing one's role as a contractor.
I had this advice given to me by one Mr Lim, a main contractor, when we first started out :
When you have the customer asking you for opinion , information, tell him, " I am here to do the work under the instruction of Mr So-and-So ( the main contractor ). I know and can do just that. More than that, please refer to Mr So-and-So." With this work policy, you can have a lasting working relationship with your main contractor.
Many contractor don't see it this way : To the sub con, the main contractor is his customer. The customer of the main contractor is NOT the customer of the sub contractor. Thus, the sub con does not take order from the customer or deal with him in any direct manner.
