Ah yes, now I remember why one never asked second-hand book dealers for discounts, in my youth. Bookride remembers too

“One must not forget the Birmingham dealer, who on being asked for a discount for books would tear them in half in front of the customer. What particularly irked him was the phrase ‘What can you do on this?’ A red mist would descend and he would reply ‘I’ll show you what I can do on this…’ and tore up the book.”