If there were a simple one-size-fits-all solution to these problems, there wouldn't be a need for a handbook, nor for a discussion, would there? I can't design

If there were a simple one-size-fits-all solution to these problems, there wouldn't be a need for a handbook, nor for a discussion, would there? I can't design everybody's systems here, but I was hoping that sharing some war stories that have cost me days or weeks of work might sensitize somebody to a few non-obvious footguns.