Comment by memetherapy

Yeah, I find this a huge problem especially with junior devs (by which I mean those within the first five or so years of their career. When you have people calling themselves senior devs after six months the job title has become meaningless). Until you've been around long enough to understand how large code bases (in general, not the one you're working on!) evolve over time and why common trade offs are made you're not going to be able to grok the weaknesses of an existing code base quickly. Start off by being humble and asking why certain things have been implemented in the way they have, there is usually a reason. Sometimes it's even a good one!