So many, but let's start with firearms as I've been binging cop/drug/special agent shows lately and I'm grumpy
 
	
		Bullets do not "spark" on impact.  
	
	
		Protagonist shoulder impacts - especially around the clavicle destroy the entire arm.  It's done.  If it nicks the deltoid, maybe...but a solid hit anywhere around the joint and it's game over.
	
	
		Reloading.  It's a thing
	
	
		Hiding behind cars.  Not a thing.  Pistol rounds maybe.  Rifle rounds, outside of the engine block, are passing through.  Especially the doors.
	
	
		Pistol accuracy - when did every cop, every criminal, and every agent learn to shoot their sidearm with the accuracy and efficacy of a tier 1 operator that spends tens of thousands of rounds a week in practice.
	
	
		Suppressors.  They are not "silencers", they are suppressors.  And unless they are using sub-sonic ammo, and even that isn't "silent" it's still loud.  Especially inside.  A suppressed, sub-sonic .22lr is the only thing that comes close to "Hollywood quiet"
	
	
		Vests - they can stop many pistol rounds, but you will often have cracked ribs and internal bleeding as a souvenir.  
	
	On to explosives
 
	
		Grenades make a very loud "pop".  There is no fireball.  They don't take down buildings.  It's not like a can of gasoline ignited.
	
	
		Cars when they catch fire don't explode.  They burn aggressively, but they don't explode like a 55 gallon drum of gasoline