1. The Know-it-all.

You know which one this is. They're the ones that from the first step into your store they think they can do your job better than you. Making their food? They could've cooked it better. Looking for clothes? They're a fashionista. No matter what they're looking for, they assume they can inevitably do it better than the person getting paid to do it. Chances are, they will complain.

2. The "Let me speak to your manager."

After endless complaining and frustration, this customer refuses to take the workers word for it. They have to hear it from a higher up. Won't accept their coupons because they're expired? They need to hear it from the manager to believe it.

Nine times out of ten, the manager will repeat exactly what their worker said first.

3. The messy ones.

No matter what they're doing, they somehow manage to make and leave a mess. It can be leftovers, shoe boxes, clothing hangers and the list goes on.

Somehow, someone gave them the idea that they can leave whatever mess they want and someone will gladly come and pick it up for them because that's what they "get paid to do."

4. The oddly generous ones.

They offer you coupons to whatever place they work at, they give you a nice tip and even some good conversation. These are the ones you tend to appreciate; they don't come often but they're appreciated every time.

5. The shoot-your-shot ones.

I don't know if it's the apron, the messy hair or the tired eyes; some people really do believe that calling you cute or complimenting you when you're most certainly not in the mood is the best way to win your heart.

They are the ones that leave their number on their receipt, try to ask you out on a date when you're just trying to get what you need to done and the ones that take any opportunity to think you're hitting on them back.

6. The sticky hands.

These are hardly considered customers. They try to snatch something when you're not paying attention or when they think they can get away with one more if they grab it fast enough.

"Are you going to pay for both of those? Or just the one that you took earlier?"

7. The ones that cut it too close.

Yes, we technically close at 9:00. No, we don't want to serve you at 8:58. You're officially pushing it.

8. The way too picky ones.

"Can you move this over? Can you get me a cleaner one? Can you spread it out evenly so that it 'tastes' better?"

It seems like there is no winning with them. Chances are that when they're done, they will still complain that something is wrong.

9. The regulars.

You know their name, their order and what they like. You're practically best friends.

10. The low-key problematic ones.

These tend to trick you; you think they're nice and all but then they start being critical and take advantage of the fact that you guys were so friendly two seconds ago. Sneaky.

11. The nosy ones.

They come and want to to know everything about you. Why do you work there? What are you studying? Do you like it? All of a sudden, you're starting to question every life decision you've ever made.

12. The foreign ones.

Didn't do well in your language course? You're gonna regret it now. Especially working in a mall, you'll come across all kinds of tourists with all types of dialects. Some you won't even be able to decipher without several hand gestures.