Theoretically no such thing as true randomness exists in a normal working computer.there's no such thing as LUCK. it was created by humans it doesn't actually exist!
In practice (pseudo-) random numbers generators are sufficient to simulate true randomness. Unless you are playing with the merciless precision of TAS-Bot, hand-eye-coordination isn't enough to make a game react always the same.
Where is the skill when trying to catch Pokémon? You can vastly increase odds by draining HP, inflicting status ailments and using different Pokéballs, but you can't be sure to press the button in the correct millisecond for a guaranteed victory (=catch).
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What I always wondered is if some games have an RNG value determined at start to modify odds in game for the following session. Sometimes I get the feeling Mario Kart Wii for example will constantly spam the player with the blue shell, the [POW], the lightning , one after another in almost every race; to the point where it becomes ridiculous to believe this is "bad luck" in each race. That is the point where I stop playing Mario Kart Wii. Other times the opponents aren't as lucky and the player actually gets a chance.