u/ElixirStylish

A thing I see pretty often: junior devs open an execution plan, notice one big expensive-looking step, and lock onto that right away.

But the real issue is often somewhere else. Bad row estimates, missing index, messy join logic, parameter sniffing, key lookups, or just reading the plan without enough context.

What mistake do you see most often?

Could be stuff like chasing cost percentages, treating every scan like a disaster, or not comparing estimated vs actual rows. Also curious what helped you personally get better at reading plans, because most people learn this part the hard way.