The first two paragraphs of this story from "Surely You're Joking, Mr. Feynman!" illustrate your point well:
> The first time I was in Las Vegas I sat down and figured out the odds for everything, and I discovered that the odds for the crap table were something like .493. If I bet a dollar, it would only cost me 1.4 cents. So I thought to myself, "Why am I so reluctant to bet? It hardly costs anything!"
So I started betting, and right away I lost five dollars in succession--one, two, three, four, five. I was supposed to be out only seven cents; instead, I was five dollars behind! I've never gambled since then (with my own money, that is). I'm very lucky that I started off losing.
One time I was eating lunch with one of the show girls. It was a quiet time in the afternoon; there was not the usual big bustle, and she said, "See that man over there, walking across the lawn? That's Nick the Greek. He's a professional gambler."
Now I knew damn well what all the odds were in Las Vegas, so I said, "How can he be a professional gambler?"
"I'll call him over."
Nick came over and she introduced us. "Marilyn tells me that you're a professional gambler."
"That's correct."
"Well, I'd like to know how it's possible to make your living gambling, because at the table, the odds are .493."
"You're right," he said, "and I'll explain it to you. I don't bet on the table, or things like that. I only bet when the odds are in my favor."
"Huh? When are the odds ever in your favor?" I asked incredulously.
"It's really quite easy," he said. "I'm standing around a table, when some guy says, 'It's comin' out nine! It's gotta be a nine!' The guy's excited; he thinks it's going to be a nine, and he wants to bet. Now I know the odds for all the numbers inside out, so I say to him, 'I'll bet you four to three it's not a nine,' and I win in the long run. I don't bet on the table; instead, I bet with people around the table who have prejudices--superstitious ideas about lucky numbers."
Nick continued: "Now that I've got a reputation, it's even easier, because people will bet with me even when they know the odds aren't very good, just to have the chance of telling the story, if they win, of how they beat Nick the Greek. So I really do make a living gambling, and it's wonderful!"
So Nick the Greek was really an educated character. He was a very nice and engaging man. I thanked him for the explanation; now I understood it. I have to understand the world, you see.