Printing debug messages didn't do much for me for this one time where a class was overflowing a buffer right in the constructor, and everything was fine creating an instance of it, passing it around, etc., until I actually go to use one of its methods later on in the program and it crashes. It was C++ on an ESP32 and I had to decode the stack trace and everything to find it, took me hours because I had to learn what even to do with a stack trace. The Espressif forums kinda suck balls, they are a ghost town.