In 2002, you started seeing major increases in query run time with as little as 5 joins. Once you hit six you had to start thinking about rearchitecting your data or living with slow response times.

There was a lot of pressure to relax 3NF as being too academic and not practical.

Around then, I had a friend who was using a pattern of varchar primary keys so that queries that just needed the (unique) name and not the metadata could skip the join. We all acted like he was engaging in the Dark Arts.