Re: DnD 5e: Using Push and Knocking Into Objects/Monsters
Pushed down a flight of stairs, over a ledge, in to a pit, on to your comrade (who has a sword, knife, or other sharp object which may stab in to the one pushed), pushed on to a Grease spell area (slides are no fun backwards, especially if your not expecting them), especially if it is one of the flammable Grease effects (pushed in to Grease zone, then someone sets zone on fire). Pushed in to a fire, in to path of big monster or berserker.
Push can be a very dangerous spell if used right. It's all about when, where, and what you can shove the target in to for best effect. Also (and this is one I have always thought should apply) the one pushed Should have to roll a Dex save to see it they fall down. That could have other effects to, fall wrong and you can break something (I broke my wrist cause I fell wrong once).
Also nothing in the Push spell says it has to be a Living target. Push a heavy object off a high spot and you could squash someone. Or use it to cause a catapult effect, at the correct angle of pressure you could send objects flying through the air. Pushing someone back 10ft is a good amount of pressure after all.
Try it sometime, you will see just how much force it takes to move something 10ft just by pushing on it.