The events that matter to your business are usually the custom ones.
We find all custom gtag('event', ...) calls on the page, validate event naming conventions (GA4 has strict rules about reserved words, character limits, and parameter formats), and identify custom events that may not be reaching GA4 due to syntax errors or wrong parameter types.
GA4 ships with a handful of automatic events (page_view, scroll, click, etc.) but every business-specific thing you care about — newsletter signups, video plays, downloads, form submissions, demo requests — has to be tracked as a custom event. If those events are malformed, GA4 silently drops them or maps them to the wrong place.
A SaaS company fires demo_request when users book a demo. The event has a parameter called plan_interested_in — but the value contains the full plan description (200 chars), which exceeds GA4's 100-char limit. Every event lands but the parameter is truncated. They can't segment demos by plan tier.
An e-learning platform fires video_50_percent instead of GA4's recommended video_progress format. The events are recorded but don't show up in the standard video reports — instructors can't tell where students drop off in lessons.
A news site uses a hyphenated event name like article-share which GA4 silently converts to article_share. Their dashboards configured against article-share show zero data — and nobody knows why.