What do you wish you knew before you started automating your trading?

Summary

• The post is a general inquiry from a trader transitioning from manual to automated trading, asking experienced practitioners what they wish they had known about pitfalls in backtesting, optimization, and execution.
• No specific asset, strategy, or investment thesis is presented; it is a discussion prompt, not a trade recommendation.
• Quality assessment: Simply a request for advice / noise — no original research or data.