Marty Weiner on how to “Learn to stop using shiny new things and love MySQL” ( emphasis mine ):

Through the gauntlet, two of the most important lessons I learned building Pinterest were:

– Don’t be the biggest. If you’re the biggest user of a technology, your challenges will be greatly amplified.
Keep it simple. No matter what technology you’re using, it will fail.

If failure is inevitable, then knowledge about how a system can fail is invaluable.