[0] Backfilling Funnel Steps What happens if someone skips one of the steps in the funnel? [Funnel Visualization] The Funnel Visualization report backfills any skipped steps between the step at which the user entered the funnel and the step at which the user exited the funnel. For example, let's say your funnel is defined as /step1 > /step2 > /step3 > goal, and a user navigates from /step2 to goal, skipping /step1 and /step3. In the Funnel Visualization report, you'd see an entrance to /step 2, a continuation to /step 3, and a continuation to goal. [Goal Flow] 
The Goal Flow report does not backfill steps. You will see flows from the originating dimension to the first step in the funnel that the user saw. You may see flows that skip a step altogether.