It isn't a job like a normal job where there will be internal politics, fighting for promotions, disillusionment at not being appreciated, worried about job security etc.
Players do 20 hour weeks, if that, have to do no real thinking other than football related stuff. People are complicated and all that but I struggle to see how truly discontented they can be other than being linked to the managerial staff which lets face it is turns over at a rapid rate at nearly all clubs. Plus they themselves expect to move around so again that should put any grumbling into perspective - they aren't at Fords for life,
Lambert said something similar after he signed for Liverpool but swiftly forgotten after RK re-energised the squad. Same will happen here hopefully as no grumbling will have any real roots.