Mentoring really only works if the junior person actively seeks out a trusted colleague, ideally in the context of a formal program (with clear guidance on expectations and such).<p>What you have here, basically, is a customer abusing an API. This is extremely common: mental models of systems differ greatly, and 'getting things to work from my side' will always take precedence over 'making sure I'm not missing an alternate understanding of the bigger picture'.<p>But one, possibly easy, thing you can do, is make the API more abuse-resistant. Add rate limits on expensive operations that should only be used seldomly (which may be hard in the case of "a SQL object", but still), just deprecate and/or hide such functionality completely, or add convenience functions that automatically do the right thing, and promote those.<p>If you do decide to reach out, make sure you very clearly describe the issues you've observed in a strictly technical way ('Hi, I noticed you're creating lots of Customer objects, which is really expensive since there are manual checks by various departments involved with that later on') and clearly outline solutions ('What you might want to do instead is only create Branch objects, which are basically what you want anyway and much cheaper and bore performant').<p>And be mentally prepared for not getting any response, them turning things around and responding that <i>you</i> are the one who's wrong, or even them running to their manager telling them <i>you're</i> impeding their progress by having way-too-hard-to-use systems. And just shrug that off, after briefly considering whether they may have a point, and making things better, for everyone, just in case they do...