You are mistaken if you think that the abundant use of interfaces etc. is motivated by anything along those lines. As someone who often puts basically everything behind an interface and abstracts everything in sight, it's not because it has anything to do with being smart, quite the opposite; it's the only way I can keep any meaningful portion of the code in my head. Give me a 5000-line straightforward / unabstracted implementation of something and I'll struggle, but give me thingDoer.doThing(), behind an interface so I don't even have to know how to construct one, and I'll be happy and able to focus on the task at hand. This applies even if I'm the one who wrote the ThingDoer interface and its implementation(s), and even if it was only 30 minutes ago.