The biggest premature optimization trap I've fallen into isn't code performance — it's process optimization. Building elaborate automation workflows, setting up complex CI/CD pipelines, creating detailed SOPs... all before you even know if the product has legs.
My rule now: don't automate anything you haven't done manually at least 10 times. By the 10th time, you actually understand the edge cases and can build something that works. Before that, you're optimizing a process you don't fully understand yet.
Same applies to code: ship the straightforward version first. If it's slow, you'll know exactly WHERE it's slow because you'll have real usage data. Profiling beats guessing every time.