A thousand times this! At the very least, I always want to have good mental model of how something probably works or mostly works even if I couldn't reproduce the implementation line-for-line. To me, it can almost be dangerous to have the power to use something without any idea of what's under the hood. You don't know the cost of using it, you don't have a good basis for knowing what the tradeoffs and reasons are for using it over something else, and the concept isn't portable if you need to work in a language or environment that doesn't have it.
If I come across a feature I like in a programming language, I usually find myself trying to figure out how to implement or emulate it in a language I already know (ideally one that won't hide too much from me). Implementing coroutines in C using switch statements, macros, and a little bit of state for example.
Since I've taken cars apart and put them back together, that has been very helpful to me in improving my driving skills. I also know when a problem with the car is just an annoyance and when I have to get it fixed. I can often know what to do to get the beast home again, without having to call a toe truck.
If I come across a feature I like in a programming language, I usually find myself trying to figure out how to implement or emulate it in a language I already know (ideally one that won't hide too much from me). Implementing coroutines in C using switch statements, macros, and a little bit of state for example.