What's the most useless metric you've tracked before finding the one that actually mattered?

Spent a chunk of this month checking metrics I assumed mattered and found out they didn't.

Checked AI Overview traffic on three real sites in Search Console. Zero clicks, zero impressions, across all three. The AI search panic did not show up in the data at all, backlinks and normal indexing did all the actual work.

Checked how far my own X replies traveled. Follower count never moved the number once. What decided reach was entirely which post I replied under, one reply hit 1,204 views because the parent post had 1.9 million, the rest sat at single digits under smaller posts.

Here on Product Hunt the surprising one is Contributor. It sits at 0 out of 5 no matter how many comments I write, because it only counts the room reacting to me, not me posting.

Three different metrics I assumed were about effort and turned out to be about someone else's reaction instead. What's the one you tracked for a while before realizing it was measuring the wrong thing?