That's the temptation of gambling. You always want to place ONE more bet as you're quite convinced you're going to win that one (and thereby for example cover your costs). However, what happens when you loose that bet is that you are going to try to place another ONE bet (probably with a bigger amount of money or BTC).. All in order to cover your costs. And then you're too deep into the game.
See gambling this way: as the house wants the casino / website to be profitable, in the end you will loose money. Yes, there is a chance that you actually make money (and some are lucky enough for this - but, in the end, the chance that you loose is bigger. If you really want to gamble, only use money you can really afford to loose.
For example, if you would otherwise spend $50 in a club that night, you can also spend $50 in a casino. But if your financial status is that bad that you can not loose a few dollars, simply don't gamble. Keep your money, and if you've got some spare; SAVE IT as harder times will aways come.
Exactly the point harharhar tried making, gamble with money you can afford to. He gambled with the money he think he could afford losing and it benefited him positively, so ofcourse even if he loses, it won't be such a bad thing. Gambling is something I was never really good at, but I've seen lot of people be successful by gambling. They take risks in casinos, in real life. Nothing bad with the idea