The single biggest mistake in Performance Max
The single most common PMax failure pattern we see in audits: one giant asset group covering everything the business does, fed with stock imagery and a single weak headline pool, with no audience signal and no account exclusions. Google's algorithm does exactly what you would expect — it optimizes toward the easiest conversions, usually brand searches or low-quality remarketing clicks, and the campaign reports great CPA while adding almost no incremental revenue. The fix is almost always the same: segment into 3–5 asset groups, seed each with a strong audience signal (customer match list, CRM upload, or a tight custom segment), exclude branded queries, and require a real creative library (at least 5 images, 3 videos, 10 headlines per group). That is 80% of what good PMax management looks like.