There's a captain who regularly asked for less fuel than the flight plan called for and got it. FOs objected in various ways (face to face, pro stan, avoid fly with) and captain was counseled by CP. He learned his lesson--he contacted dispatch to lighten fuel load before the flight plan was generated so the FOs wouldn't know that he had asked for less fuel. FOs eventually caught on to this as well and after a divert it may have stopped. It takes all sorts.