I've

- read that from start to end exactly zero times,

- picked up generics in a day or two,

- struggled with advanced types twice, half a day each time

- struggled with type erasure twice, also about half a day each time.

Meanwhile generics often saves me a number of minutes pr hour and makes everything cleaner and easier to read.

I used Java before generics but once it arrived I never looked back and neither did anyone i know.

Java before 5 wasn't a language, it was a library and number of jvm implementations. It wasn't until Java 5 that there was a memory model spec that defined how stuff was supposed to work.