Lex had long been disillusioned to his own reality. He knew he wasn't exactly a good guy based on the traditional definition of things. Although he tried to avoid killing people, the number of beings who had died by his hand was so immense that he actually had no idea what the number was.
At the same time, he usually took a bit of pleasure in making his enemies feel hopeless. In watching them build up hope after almost peeling away defenses, only to realize that his body was, in every metric, much stronger than the actual armor that he wore.
But such things were reserved only for his enemies. Lex did his best to stay polite and amicable towards people on an ordinary basis, and though he had goaded the panther a bit into revealing details about the glass containers they arrived in, the way that Lex saw it, the bank owed him that much after getting him involved in some random confrontation.
