One sign of maturity is taking responsibility for your actions. Individuals who still play the blame games are irresponsible gamblers who should not be gambling in the first place, and that is a sign of immaturity. These kinds of people are the exact kind of persons that you should be cautious when introducing them to an opportunity, not just gambling, even if they feel or have an interest originally, because at the end of the day they may end up blaming you for whatever the outcome of the action that they took with their own hands.