I completely lose it at a "Customer".

[Sandiercy]

I work at a game store in a mall. We have an outside door and a door that opens into the mall. The outside door has signs on it that say "no exit" and are quite visible from the mall door. The only reason why we cannot lock the door is that it is a fire exit.

Me: awesome game store manager.
SC: young punk who thinks that the world owes him a favour.

Quick Background, this SC was in here yesterday and went through the fire exit door and was told clearly that he could not go through there. Cut to today.

SC walks through store and heads towards 'the' door.
Me: You cant go through that door.
SC: You cant stop me.
Me: *Raising my voice* You cannot go through that door!
SC: *Pushes on door and opens it* If I cant go through this door, then why is it open?
Me: *shouting now and walking towards him* THAT IS BECAUSE YOU JUST OPENED IT, YOU LITTLE FUCKFACE, GET THE FUCK OUT NOW!!!
SC: *backing off a bit* See you tomorrow, I will be coming through that door no matter what and you cant stop me.
Me: *Slams the door in his face*

No, I will not get in trouble for this as the boss is a feisty Portuguese man who is essentially Gord 2.0. He lets me yell at people like this.

[csquared]

A challenge! Who will win?

A chat with mall security on your options could be interesting. Maybe you could have him arrested for trespassing.

[It's me]

Fire Exit needs an alarm! Even if a manually triggered airhorn right beside it

[BowserKoopa1]

Set a trap for him Just act like you don't care.... Naw, he'd get suspicious then. Get mad like you did before, and have security waiting outside the door for him.
Also I think you forgot the law about sucky customers, if there is even one.... If you tell a customer not to do something, they will go ahead and do it anyway. Why? Because they are "customers", and as such, they think they should be treated like royalty and be able to get away with whatever the fuck they want. And they expect managers to let it slide because they think the managers will want their business (sadly their are a few spineless managers who will do this just to make a couple of lousy bucks )
On the flip side, you could use reverse psychology on them and tell them you don't care if they go through the door anymore. That will get them thinking, "Should I go through the door? Should I not?" Fun stuff to watch.

[MadMike]

My son did maintenance work at McDonald's a couple years ago. He told me that he was having to constantly reset the alarm when some idiot decided to open the emergency door in the play area. And no, it wasn't little kids doing it, it was more often then not the parents, who clearly should have known better.

[AmbrosiaWriter]

Actually, you can stop him.

Ban him from the premises. Anytime he even enters the store it's trespassing. Teach that little fuckwit some manners.

[emax4]

Better yet, change the sign so it reads, "Ignorant Douchebags who have no life, Please Exit Here!"

[Teskeria]

or how about a sign that says 'This door is only for ignorant worthless douchebags.'

And when he opens it, a loud 'Hey everyone! Look! It's an ignorant worthless douchebag who ADMITS to being one!!!'
After all, by using the door, that is what he did. In the event of a real emergency, tear off the sign.

[emax4]

I LOVE IT!

[RootedPhoenix]

I vote for keeping a vuvuzela close by. Every time this turkeybrain opens the fire exit....it's vuvuzela time!

The other option is some airhorn thing, but somehow I like the vuvuzela better.

[Sapphire Silk]

or how about a sign that says 'This door is only for ignorant worthless douchebags.'

And when he opens it, a loud 'Hey everyone! Look! It's an ignorant worthless douchebag who ADMITS to being one!!!'
After all, by using the door, that is what he did. In the event of a real emergency, tear off the sign.

And the best part is, with the culture of gamers no one will bat an eye, get offended, or come to the SC's defense!

[Kagato]

If I caught him trying to get out through that door it would probably go something along the lines of the following:

Me: Please empty your pockets and let me check your bag, sir
SC: Why?
Me: For all I know, you may have just shoplifted from our store and are trying to sneak out our fire exit.
SC: You can't make me.
Me: I can't, but Mall Security can. Please wait inside the store while I call them, any attempts to leave without showing me what, if anything, you are holding, will result in me calling the police.

Knowing he would be searched every time he tried to go through the door, potentially keeping him an extra 10-15 minutes (or longer if you decided to draw the agony out for him >_> ) he would soon get the hint and find another exit to leave by, at which point he is no longer your problem.

[MrSmiley]

To be fair, if he's a gamer he's probably waiting for an invisible wall to prevent him from going further in the open world.

[Jester]

I worked at Chain Restaurant for five and a half years. At that location, we had two emergency exit doors which were clearly marked, in large capital letters, "EMERGENCY EXIT ONLY. ALARM WILL SOUND."

Anyone wanna guess how often in those five and a half years someone went through one of those doors? If you guessed "at least once a day, every day," congratulations, you're dead on!

[OfficeSlug]

To be fair, if he's a gamer he's probably waiting for an invisible wall to prevent him from going further in the open world.

If one had the time & inclination (and a bit of permission), OP could saran wrap the doorway outside the exit door, thus creating an "invisible" wall for the young punk - and giving those inside the store some serious LULZ.