In my opinion, someone gambling for fun understands and accepts that they are likely to lose the money they wager. The money spent is viewed as the price of admission for the entertainment experience, not an investment or a serious attempt to get rich. Losses are seen as part of the game, not a catastrophic event. 
Well said and this is the best definition of gambling for fun i have come across in this thread because if we have the mindset that we are gambling for fun, the first thing that comes to the mind is probable losses so that even when we win along the line we can considered it more fun since a reward have been attached on our way to having fun. Gambling is not something we engage in with the belief to make profits or ends meet from it so that it will give anyone that wants to develop interest not to see it as source of income and to have a sense of belonging not to spend much money on gambling since profits is not promised.