Play for fun. If you are not playing for fun, you are doing it wrong. Gambling should be done to entertain yourself only, and always remember that gambling is not a sound financial investment. I have witnessed the horrors of people who blow their kids college funds and life savings on gambling at a Casino. Don't be one of these people. Have a daily or weekly gambling budget and learn which games you like and how to play them so that you can actually have much more fun playing them than just winging any game.
I sort of disagree with you because if you playing entirely for fun, then you cannot take it seriously. Have you forgotten that the gambling industry is worth billions of dollars? If you play for fun, you might not know the importance of discipline, seriousness and commitment and this is not how to survive in a multi billion dollar industry. You can catch fun while playing but it should never be the driving force for venturing into gambling.
I have always been an advocate of developing a strategy that integrates, risk management, style of play, winning targets and when to stop playing. If you have developed this system and follow it religiously, the fun will come naturally because it will take away the pain of loosing beyond budget.
By the way, what other fun is greater than having huge and winnings? With the money, you can get all the fun in the world!