Not even necessarily an outsider. In my experience "Can't you just ..." is what the rubber duck [1] starts saying if explaining the problem wasn't enough to be

Not even necessarily an outsider. In my experience "Can't you just ..." is what the rubber duck [1] starts saying if explaining the problem wasn't enough to be enlightened and it starts talking back. Simple solutions to complicated seeming problems are usually from coworkers not directly involved with the issue that say "can't you just..". [1] For those not following, Google 'rubber duck debugging'. Colleagues are the best rubber ducks.