... because we all know that calling someone a GIRL is the go-to insult for guys who hit their life-apex on the tether-ball court. Holy crap man, go for the big artillery... I'm thinking you need to pull out some scorchers like:

"Nuh-uhh.."

or maybe the super-atomic death defying

"I know you are, but what am I?"
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The charm of fishing is that it is the pursuit of what is elusive but attainable, a perpetual series of occasions for hope. -John Buchan