It all starts with small amount of losses until it grows, until the emotion comes in and control is gone. Until you can no longer feel of what you are before because what's important to you is to win back your money. That's why you become quick to anger, hard headed and you listen to nobody. That is near to the utmost bad effect to a gambler. If by simply talking to you, you're no longer chill and you get easily mad by few talks. You better sign up for an expert that will assess your behavior because you might be having a behavioral problem that's very common to gamblers.
Problematic gambling can start from little loses then degenerate to bigger problems that will affect the gamblers and people around them. Any gambler that doesn't have self control will eventually go from their normal chasing loses into serious chasing and if they're not achieving the winnings that they want aggression will follow and eventually affecting their relationships with their loved ones. This is when full blown addiction will manifest and they can become out of control if they don't get help. Family and friends that notice one of their own developing aggressions they should monitor the person to see if he has become addicted to gambling.