After he gave the gold coins to the old man, the librarian stared greedily at the gold coins for some seconds unable to believe his own eyes, but he quickly adjusted himself and thanked the customer, however, Arthur ignored him, he picked the books and left the building, the old man didn't stop speaking as he shouted at Arthur to come back if he needed any sort of book .
'He who is not contented with what he has, would not be contented with what he would like to have' even though the old man got a whopping 220 gold he still wanted more, human greed is really the worst thing in them.
...Author... just stop...
because a business owner trying to get a high paying customer to return is definitely the dangerous and evil greed of humanity... It's not like they're just trying to get enough money that they can live well.
Greed only becomes a dangerous trait when the person's demand for something will never be satisfied, and they'll go to any length to try and collect that thing anyway. So if I loved gold, and I could never get enough, and so I ran around killing anyone as long as they had gold. That would be when greed becomes a legitimately negative trait. Did the old man do something like that? No, he's just running a business. Just chill out with the 'humans are inherently evil and disgusting' ****, man. If you're going to try and talk about the greed that humans can hold in their heart, at least think about what's actually happening in the story you're writing first.