Spoiler alert: The house doesn't win by getting lucky. They win by using math against you.
You might hear gamblers say a machine is "loose" and pays out a lot. This is a misunderstanding of two basic math concepts:
High variance tricks your brain into thinking you can win, because the peaks are higher. But gravity (Expectation) always pulls you back down.
Actually, yes. But they are legally rigged against you.
State gaming commissions require machines to have a minimum "Return to Player" (RTP)—usually around 85% to 95%. This law guarantees that the machine keeps 5% to 15% of all money put into it over time.
By law, the machine is a Supermartingale. A Supermartingale is a math term for a game where your expected wealth goes down every single time you play.
The most common strategy is: "I'll just stop the moment I'm up $20!"
Math has a rule for this called the Optional Stopping Theorem. It proves that you cannot take a losing game (a Supermartingale) and turn it into a winning game just by picking a clever time to walk away.
If you play 100 days and stop as soon as you're "up" each day, you will have many small winning days. But the few days where you never get up will result in massive losses that wipe out all those tiny profits.
Let's simulate 1,000 separate days at the casino. You bring $100 each day. You stop the SECOND you are up by $10. Otherwise, you play until you lose your $100.
Notice the chart. Even with hundreds of "winning" days, the massive losses drag your total wealth into the dirt. Don't fucking play.
Test your brain against casino psychology.
Scenario 1: You flip a coin and it lands on Heads 5 times in a row. What are the odds it lands on Tails next?
Scenario 2: A guy next to you just hit a massive jackpot on a Video Poker machine and leaves. Should you sit there?