As programmers we often have to mentally run code. To imagine how a program will behave given certain inputs. This is hard enough for experienced developers. But for juniors? It can seem impossible. In this article, Melissa Williams argues that pry is an invaluable tool for junior rubyists because it allows them to see exactly what is going on as their code is run. https://www.honeybadger.io/blog/debugging-ruby-with-pry/