MVP ≠ low-quality V1 – shipping half-baked core experiences burns trust; test the claim, not polish, unless polish is the claim.
No thresholds – without pre-set pass/fail lines you’ll rationalise any result.
Wrong audience – testing with non-buyers gives false negatives/positives.
Vanity metrics – pageviews and likes; prefer conversion, retention, WTP, unit economics.
Ethics & brand risk – fake doors: be transparent, capture interest, and follow up; don’t charge without fulfilment.
Scaling too soon – “success” on tiny samples can vanish; re-test on a larger cohort first.