Honestly, I've worked in retail before, and often hear this from people. But these people have not been in a job like retail.

So is the customer always right?

Honestly, no.

Should a store strive to keep customers happy? Yes. But that doesn't mean letting customers walk all over you because of the common phrase "the customer is always right"

If this was something constantly followed, stores would not have the money to stay open.

Everyday I hear "the gas pump charged my card 75 dollars extra. I didn't know it would do that. You should give me the money back because I need that money"

No, I shouldn't, because if you read your card terms from the bank, I guarantee it's listed in there that paying at the pump will hold extra off.

One customer tried to say she found a hair in her food. Then brings a kinky curly dark string of hair up and said "the other worker made it"

What other worker mam? The other worker is a man with short hair.

So, I personally feel like no, the customer is not always right, and is sometimes just being an asshole.