Ask why five times
This sentence comes originally from the book The Toyota Production System by its inventor, Taiichi Ohno, although I’ve also read it in more recent books about entrepreneurship.
The point is trying to find the real reason for a problem. If you only ask why once, you won’t get the real reason, but rather only the first thing that comes to the mind of the person you are talking to. Besides, asking why five times requires teamwork and sharing common goals, not to blame other departments/people about the things you couldn’t do well.
It’s hard to get to the final one, whether it’s the third or the tenth, but I can assure you that it’s worth the effort.