No gambler treated gambling as entertainment all the time he is playing, there will always be a time of changing or shifting your mindset, we are tempted to be like that, we are just humans and tempted to be greedy especially when money is involved.
It's mean your self control skill is bad and you need to think what's the reason your mindset is changed. I was a gambler who gamble for money, but mostly I didn't achieve my goal and I'm not happy with the result. After that I learn to change my mindset to gamble only for entertain, regardless of the outcome is, I always happy since gambling is fun. Until now my mindset is never changed and gamble is always to entertain for me.