A good line in haggling is always more along "IT's such a gorgeous animal, I really want it but I could only afford $XXX..."

A bad line in haggling is more like "Dude, that's trash, Breeder X has twice as good a snake for half the money! I'll take it for $XXX but I'm doing you a favor cause it's ugly."

And yes, I've heard "negotiating" just like that. I try really really hard to speak highly of any animals. Once last year(I think?) I was looking at some cinnamons on a table and and chatting with the seller and "Well mine are way prettier than these..." popped out of my mouth. I was so appalled... stumbled for something to say to make it sound nicer and then slunk off feeling like there was a giant blinking sign on my head saying "JERKFACE" for the rest of the show.