One of the major disadvantages of being a consultant is that you usually have to fit in with the incumbent way of doing things. Despite being able to bring knowledge and experience to a team, you are often found toe-ing the line despite your best efforts.
In the past I have been in positions where I have been given the mandate to implement sweeping changes to a project development processes, but was blocked from implementing all but the smallest of these changes in an effort to appease staff that just would not make any effort to change.
In other locations I have seen permanent developers with so many years invested in a certain way of doing things that they are unwilling to accept constructive criticism or alternate views. Of course their expertise in these systems makes them invaluable and inviolate, and so the status quo continues.
Of course one of the things I have been learning is how to better introduce change and keep team morale high, so I am getting better at this, but sometimes you just wish that you could put the politics aside and just make things happen.