Pardon me, could you take out your credit card for a moment? You don't use one, just your debit card? That's okay, take it out. Yes, right now. Alright now that you are looking at it, do you see all those numbers on the front? They look very important don't they? They are not.
Flip the card over. Yeah, to the back—you got it. Now do you see that smooth band running along the top? That is the magnetic strip. It is actually the brains of the whole card. Touch it. Go ahead, you get to feel a card's brain! All the information your card contains is located in that strip.
When you make a purchase, this strip is the section that needs to be inserted into the machine—not your bumpy numbers. Does that make sense? So the next time you force your card repeatedly through the machine, and you hear a grinding sound and a message like "card reader error" keeps flashing in front of you, please don't assume that somehow the stores machine isn't working properly. I can almost guarantee you that the cashier will ask you to reinsert your card the correct way.
What? They all make them differently? Well that is true, they do. I think there are programmers out there saying "Now how can me mess with the American Consumer's mind today?" as they work on yet another model. Having said that, ALL MODELS READ THE MAGNETIC STRIP! And there you have it. So take a moment, and become familiar with your card. You will do yourself, your future cashiers, and the world at large a huge service. Thank you.