as Chuff says just like any other workplace.... And just like in any workplace, when junior people start trying to meddle in office politics, particularly in the PhD situation those PhD students who wander round always criticising other students and staff but never taking responsibility for their own work, then it tends to end in tears for them. Staying clear of the politics if humanly possible, being pleasant to all and sundry and getting on with your own work in a professional manner seems to me the recipe for success for a PhD student just as it is in any workplace.