[TheDong]

Gambling isn't about the chance to lose money, gambling is about the rush of feeling like you're taking risks, the thrill of winning, and the crash of feeling like you're losing.

As such, if you setup auto-invest into SPY and never look at it, you're not gambling. You don't know if you're winning, you're not thinking about it like a bet.

If you go with your definition of gambling then, well, taking your salary in USD is gambling because the USD, just like SPY, could go to zero and you lose it all.