Everyone who enters in gambling knows the chances (most sites informs you the precise percentage), so, particularly, it's pretty much wrong to cry for a loss in cards, dices or slots... I think poker has the best chance to score because it's a question of skill and technique. I think dice and slots could be intentionaly not fair and sure losses will come.
Yeah of course everyone do know the chance but to be on profit you need to ourcome their odds to get some profit. By playing sport betting is much more prefer because you can profitable in a long term if you have enough experience