gambling

Don't gamble.
But what is gambling?
Gambling is participating in an activity with -EV.
Obviously, it's not just about casinos. Buying & holding shitcoins (even during a bull market) is -EV in comparison to buying & holding an "index" (BTC/ETH/SOL, and other blue chips). 
Farming airdrops by burning your time and money without even a rough understanding of whether your EV is positive or negative, is also -EV more often than not.

But let's take a broader look at this issue.
Staying in a country on the brink of war is -EV . Even if the probability of such event is 1% - it's still not worth the risk.
Staying in contact with people who only take from you and who you wouldn't mind to never see in your life again is -EV.
Not choosing to be the best version of yourself today is -EV.