It differs with different games. In slots, the risk is way too high and you rely on what the developer written to come out next so everything is actually there and we cannot change it. We just wait for what will come next.
In sports gambling it is different too. We can actually try to analyze the game and maybe it will help lower the risk that we are taking by using the knowledge about the sport.
I have not tried other games like blackjack or roulette but I bet they have the same system as slots except the live games.