"There are a lot of things you can do with C++ (and other languages -- even C probably) that feel good at the time, only to learn later that they don't age well."
I think this reduces to the argument that you should do the simplest thing that works. As a programmer (especially as a C++ programmer), it's tempting to write clever code. It's fun. Why do something the boring straightforward way when you can invent an elaborate class hierarchy, or use that CRTP thing you keep reading about? Being a good C++ programmer requires a certain amount of discipline, but I think that's a trait that's helpful with more modern languages as well. Consider languages that allow monkey patching. It's a neat feature, but if used without discipline will lead to code that doesn't age well because it imposes more complexity on the codebase.
It's tempting because that's how we build our skills. You must abuse a tool to understand it, and know when to not use it. Unfortunately in professional contexts, many of us do that learning on the job, exhausting out a turbulent jet wake of too-clever code, upsetting those who follow. Coming across CRTP for the first time is either an upsetting detour or a fascinating David Foster Wallace style WTF-inducing endnote that you must consume before continuing. You appreciate this dynamic more as you play out different roles, both producing and consuming. Some languages try to interdict this state of affairs, shielding us from each other, but the more fun languages let us burn ourselves and our colleagues and finally learn restraint in ways you never learn in languages with training wheels.
I think this reduces to the argument that you should do the simplest thing that works. As a programmer (especially as a C++ programmer), it's tempting to write clever code. It's fun. Why do something the boring straightforward way when you can invent an elaborate class hierarchy, or use that CRTP thing you keep reading about? Being a good C++ programmer requires a certain amount of discipline, but I think that's a trait that's helpful with more modern languages as well. Consider languages that allow monkey patching. It's a neat feature, but if used without discipline will lead to code that doesn't age well because it imposes more complexity on the codebase.