Was I out of line for calling a female customer a cunt?

Okay I work as a barista at Starbucks and there is this woman regular customer who comes in everyday there who is very pretty but very mean and always criticizes the way I do my job and say things like I don’t work fast enough and then yesterday she came in being extra bitchy when I didn’t make her order to her perfection and started saying things like how hard is it to do a minimum wage job and that I must be special needs and that I’m the reason why people are against paying minimum wage workers a higher wage and then I yelled at her and said “just because you’re pretty dosen’t mean you get to be a cunt to everyone.” Now once I realized what I said I quit on the spot since I knew I would be fired anyway. I was having a really bad day when I called her a cunt and I didn’t even apologize to her because she is a cunt who thinks that just because she’s hot that she can be a cunt to everyone.
Was I out of line for calling a female customer a cunt?
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