first one is usually caused by a roach nest or prop getting under the fridge, you can still move the fridge with the broom
You push/pull harder if you move in the direction while doing so, and where you "grab" the prop matters, it actually attempts to pivot around where you started the grab, not the center of mass of the object. You can also hold sprint, then grab, and it will push even harder but it will try to prevent the prop rotating, more useful for pushing tables and such.
And for plugs falling through the floor and getting stuck through walls and such, there is a button on wired machines near where the wire comes out to reset the plug location