"Denominator engineering": when you change the constraints of the metric you're tracking when things aren't going well to make it look like it is/get an A/achieve your OKR.
When addressing a scaling bottleneck or solution, always look for an edge of scale or a test that shows the next bottleneck. In lieu of having run that test, outline how you might.
If an SME is in the room, they will be the one to fix the problem. If you are trying to spread knowledge, try not including the SME.
We set limits of a system, and we test up to those limits.
Every RFC must consider the alternative of doing nothing.
Work hard to understand what you are modeling, not just what it will be used for.