It's literally how we evolved.

Our brains get bored of steady reliable rewards. Because those always happen.

There's been studies on this, intermittent and random encouragement is more motivating than actually rewarding people consistently for their effort.

Because our brain desperately wants to solve the randomness. Reward someone for no reason and they just keep doing everything they think may have caused it, give them the reason and they just do that.

That's why so many gamblers are obsessed with their "system" and swear they've almost got it perfected. Gambling addiction isn't even a failing, it's exploiting things that are why we have houses let alone gambling apps.

The drive to solve something that seems random to maximize rewards.

I don't understand playing a game designed to make you lose, but playing online and assuming it's not fixed is just stupid.