Making sound decisions while gambling requires a clear mind and emotional control. Playing while angry, upset, annoyed, or overwhelmed can result in poor judgment and bad decisions. It's also important to remember that each game is unique, so don't get too wrapped up in one particular conclusion. I've also had similar experience with gambling when angry, I used to have this habit of gambling whenever I have a fight with my wife but whenever I indulge in gambling to calm my nerves, I always end up losing more because my emotions are always clouded and influences my decisions.
Some times all bad outcome in gambling is not because of poor emotional balance because at some point we already know that gambling outcome are unpredictable and no matter what the level of your emotional stability is, you can still lose at any game, although some time where emotional involvement can be check is when we are taking the bets and what the direction we look at it from, e.g when we surpose to take a break and we decide to take extra bet just because our last bet was a lose, this point we are chasing our loses which is not a good thing to do at any time in gambling, because regardless how you feel, the reality is that you can still predict the result of your next game.