When Mike suffers a $30,000 loss in the beginning of the film this setback and the relational damage it causes leads to his decision to quit playing the game entirely. It goes to show that mindless gambling is not the way to go and playing carelessly increases your chances of losing. However, it still subtly highlights the importance and risks of developing a gambling addiction - there is a scenario in which Mike even ponders whether he should risk his whole budget on the game. There are obvious disadvantages to offline as well as online poker, but unlike previous films on gambling, Rounders doesn’t necessarily exclusively focus on the dangers of gambling (which may be part of why it's beloved by actual poker pros). For example, at the beginning, Mike McDermott is shown losing miserably. There are plenty of life lessons to be gained in Rounders, what the film does well is recreate the suspense of playing the game the details in the skill as well as the luck that’s involved.
