Credit cards are a financial death trap when used impulsively. I'd always reserve a card that indebts me with each purchase for emergencies only.
Debit and cash are better, as you're actually spending your own money, which means no interest as you're not borrowing money and paying at the end of the month. In a sense, credit cards are a profit means through interest for the banks.
And then there's those kinds of people who go out and spend the money they already don't have on things they don't need. As one old comedian would say, "they end up maxing out their credit cards, and spend the rest of their lives paying 15% interest on something that cost $12.50. And they didn't like it when they got it home anyway." -_- Stupid, stupid, stupid.