Most of us gamblers probaly have experience that, but it's a bad attitude mate, it's like we aren't good in accepting our losses and that we would involve other people with our disappointment in gambling. It normally happen when we aren't gambling for entertainment only and we do risk money more than our budget, I would not use "money you can affor to lose", as there are times you can afford to lose the money you are gambling but it's already out of your budge, so in the end, it will have a big effect on your emotion.
I agree that sometimes even if someone has choose to gamble with money they can afford to lose, it's still possible for them to become emotionally attached to the outcome of the game, the disappointment is inevitable when the outcome takes a negative turn and the money is lost. So it's not just about gambling with money one can afford to loose but also gambling with the right mindset and attitude.
Yes, gambling money has a lot to do with behavior change. When the game becomes more than fun it is no longer just a game it is an uncontrollable urge to continue gambling despite the loss of your life. It is not right to spend more money on gambling but willing to risk something valuable in the hope of getting something of greater value gamblers bet more money to win more. Gambling is also different with different levels of behavior. As soon as the word gambling is heard a kind of negative reaction starts in the mind.