Part of the issue is that there's no way of knowing which lowlights now will affect which highlights later until (sometimes quite a while) after the fact.
For example, the sequence might go 6, 8, 4, 18, 9, 5, 14, 2, 4, 4, 10. Or it might go 6, 8, 4, 14, 9, 5, 13, 2, 4, 4, 11; the '14' is only built up by the preceding 6 and 8, the 4 goes with the 9 to give the 13, then the 5, 2, and second 4 make up the 11 at the end; the first 4 of the ending pair affects nothing.
And this is still a very simple version. Sometimes what seems like a disconnected lowlight now helps lead to a highlight three sessions from now; only in hindsight can anyone see how they tied together.