Ask HN: How do you quickly read and make comments on HN?

By the time an article's in the top 10 on HN there's already lots of comments.

I'll skim the first 20%, assuming the best stuff is at the top. But many times I'll see busy, smart people like PG inserting commentary on stuff that's below the bottom half.

Do busy people read everything even when a lot of it is junk?

What are your comment reading strategies?