Situation · Yourself

“I'm secretly happy when other people fail”

What could be going on

Envy: Pleasure at a rival's fall often comes from envy; check whether it is people who have what you want.

Ressentiment (Nietzsche): Fits if a powerless grudge toward the successful lies underneath; check for a sense of unfairness.

Social comparison: Their failure lifts your rank by comparison; check whether you feel better about yourself after.

Inferiority complex (Adler): Fits if you feel lesser and their fall evens it out; check how you rate yourself.

Vulnerable (covert) narcissism: Hidden sense of specialness plus resentment could fit; check whether you feel overlooked.

Everyday sadism: Only if you enjoy their pain itself, even strangers', not just your relative gain.