Observability is often described as the three pillars: logs, metrics, traces. That framing is useful but misses the point. Observability is the ability to ask new questions about your system without shipping new code.
Cardinality Is the Enemy
High-cardinality dimensions, like user id or request id, are where the value lives but also where the bills explode. Pick your dimensions deliberately and sample aggressively.
Tracing Earns Its Keep
Distributed traces turn black-box outages into a story you can read. Invest in them before you need them.
SLOs Over Dashboards
A wall of green dashboards reassures nobody at 3 AM. Service level objectives, with error budgets, give you a vocabulary for when to act and when to wait.
Conclusion
Build observability into your platform, not on top of it. The teams that do spend their incidents fixing problems instead of finding them.