For example: I personally loved unlocking all the characters in Smash Ultimate through the World of Light single player mode, but can see how people might not wanna wait potentially dozens of hours before they have the full roster.
I’m of the mind that all video games should have a balance between fun and slightly challenging with the balance leaning towards fun to play. Any video game that’s bullshit and frustrating gets dropped immediately. If it takes me more than 3 tries to kill a boss or a death means repeating more than a minute or two of an area then I basically drop the game for good.