I've read this book 13 years ago I remember it was fun but I didn't take much out of it. Since I'm currently exploring usability testing, this book came up again and I thought it would be a good idea to reread it.
I can say I feel exactly the same, the book is extremely surface level. 100 things is a big list and you have to compromise quality a lot. As a result the book is more fun than useful. It tries to be based on research, but at best it cites a single research paper per section and never talks about the quality of that research. I find it hard and dangerous to accept everything as a fact as there is a high chance it's not conclusive or just wrong.
If you are new to human psychology and behavioural science this is a good book to get started and get excited. Just see it as fun rather than practical.