In the 'practice of programming'. https://www.cs.princeton.edu/~bwk/tpop.webpage/ I last read it some years ago so I can't tell you exactly what they said. I do know that when pointed out I realized I suffer from the same sins they hate about debuggers: I would step through code mindlessly, changing variables and the like, but never stopping to think. While printf is more painful it forces me to think why is the code in that state, which is key to fixing bugs.

i totally agree