OK, here’s the final rule of the night: Don’t be afraid to say something is too hard. There are some things out there that are just too hard to game. No matter how much homework you do, no matter how hard you try, you will never be able to know enough to invest or trade in certain situations.

Cramer says one of the hardest plays is restaurant same-store sales growth. He admits to getting burned almost every time he’s tried. There are just too many factors at work, he says, too many different things going on that could crush you if you get it wrong.

Now, Cramer’s not telling you not to buy a restaurant stock. He’s just letting you know there a better ways to profit than banking on a better-than-expected same-store sales number.

When Cramer says there’s always a bull market somewhere, he means it. So don’t beat your head against the wall trying to make money by playing something that is just too hard.