There is a sickening feeling that happens in poker from time to time. You're all-in, your opponent is all-in, and when you flip over the cards you realize that even if you make your best-case hand you're still going to be beaten. This is what is known as drawing dead. Your outs are officially zero, and you can now stand up from the table and make a graceful exit.
The board shows 6-7-8-9 and you hold the T-J for the highest possible straight. The only problem is that there are three hearts on the board and your opponent flips over the Ah-Kh. If you're playing a drawing hand it makes sense to ensure that you're aiming for the highest possible hand on the board. If the board pairs and you're shooting for that flush be aware that a full-house is a distinct possibility. Drawing dead is a typical phenomenon in Omaha, where poker players seem unable to imagine a world in which their pretty hand is beaten before they bet.