It takes more than just Thinking to quit gambling. Gambling is an addiction hard to give up, you must think of the right reasons, reasons that really motivates you to give it up otherwise, it will be in vain.
Exactly, motivation to give up and never play again. In my own experience, i've quitted in gambling and I didn't care about gambling but it only lasted in a few months after I've played once, back to the same me again.