Depends on how you view transactions. I like term "non negotiable" for exactly this clarification. It can be simple: thing that person is selling they personal

Depends on how you view transactions. I like term "non negotiable" for exactly this clarification. It can be simple: thing that person is selling they personally value at X. If person buying wants to pay X, they get it. If I can afford not to do some weird social negotiation dance - I won't. I do realise though that sometimes I really want the transaction to go ahead so I have to do the dance. So while I am not about to endorse screaming "Did I fucking stutter!?" I can absolutely understand a person saying they want more now because you are making this process harder than it needs to be.