It is not the same case for everyone. I keep on coming back because I am addicted to play, I want to play and I have the urge to do that every single day or atleast twice a day. I keep coming back however I only use a small amount to play that is why I dont think that it will be bad for me if I keep on playing
Right the reason will be not same for everyone, but most of the players will come back again to get back their losses in gambling. In your case, you are addicted to gambling so you are indirectly addicted to free money, or you addicted to gambling games because of this 2 reasons you will come back. I am not addicted to gambling I play just to have fun in gambling.